DUBAI (REUTERS) – Iranian officials told Reuters on Friday (June 21) that Teheran had received a message from US President Donald Trump through Oman overnight warning that a US attack on Iran was imminent.

They spoke shortly after the New York Times reported that Trump had approved military strikes against Iran on Friday in retaliation for the downing of a US surveillance drone, but called off the attacks at the last minute.

“In his message, Trump said he was against any war with Iran and wanted to talk to Teheran about various issues...He gave a short period of time to get our response but Iran’s immediate response was that it is up to Supreme Leader (Ayatollah Ali) Khamenei to decide about this issue,” one of the officials told Reuters, speaking on condition of anonymity.

A second Iranian official said: “We made it clear that the leader is against any talks, but the message will be conveyed to him to make a decision...However, we told the Omani official that any attack against Iran will have regional and international consequences.”

Iranian state television on Friday showed what it said were retrieved sections of the US military drone it brought down. Amirali Hajizadeh, head of the Revolutionary Guards aerospace division, said on the programme that the debris was proof that the drone had been over Iranian territorial waters when it was shot down by the Guards.

The Fars news agency said on Friday Iran has told the United States via the Swiss ambassador that Washington will be responsible for the consequences of any military action against Iran.

Because Washington and Teheran have no formal diplomatic ties, the Swiss ambassador in Teheran represents American interests in the Islamic Republic. The Islamic Republic News Agency (IRNA) reported that Iran’s foreign ministry, which summoned the ambassador, had told the envoy that Iran was not pursuing war with the United States.

After weeks of rising tension amid a spate of attacks on oil tankers in the Gulf, Iran said on Thursday it had shot down an unmanned US military surveillance drone, fanning fears of an overt military confrontation between the longtime adversaries.

The New Times quoted a senior administration official as saying, US warplanes took to the air and ships were put in position for a retaliatory attack only for an order to come to stand down, without any weapons being fired.

Targets had included Iranian radar and missile batteries, the paper cited senior administration officials involved in, or briefed on, the deliberations, as saying.

The strikes were set for early in the day to minimise risk to the Iranian military or to civilians, the Times added.

It was unclear if attacks on Iran might go ahead later, it added, nor was it known whether Trump had changed his mind or whether his administration had become concerned about logistics or strategy. </s> WASHINGTON/DUBAI (Reuters) - U.S. President Donald Trump approved military strikes against Iran on Friday in retaliation for the downing of a U.S. surveillance drone, but called off the attacks at the last minute, the New York Times reported.

After weeks of rising tension amid a spate of attacks on oil tankers in the Gulf, Iran said on Thursday it had shot down an unmanned U.S. military surveillance drone, fanning fears of an overt military confrontation between the longtime adversaries.

In response, the New York Times quoted a senior administration official as saying U.S. warplanes took to the air and ships were put in position for a retaliatory attack only for an order to come to stand down, without any weapons being fired.

Targets had included Iranian radar and missile batteries, the paper cited senior administration officials involved in, or briefed on, the deliberations, as saying.

The strikes were set for early in the day to minimize risk to the Iranian military or to civilians, the Times added.

It was unclear if attacks on Iran might go ahead later, it added, nor was it known whether Trump had changed his mind or whether his administration had become concerned about logistics or strategy.

Tehran said the unarmed Global Hawk surveillance drone was on a spy mission over its territory, but Washington said it was shot down over international airspace in the Strait of Hormuz.

Trump said initially the downing of the drone could have been carried out by someone who was acting “loose and stupid,” adding that he suspected it was shot down by mistake.

“We had nobody in the drone. It would have made a big difference, let me tell you, it would have made a big, big difference” if the aircraft had been piloted, Trump said as he met Canadian Prime Minister Justin Trudeau in the Oval Office.

The destruction of the drone compounded tensions escalating in the Gulf region, a critical artery for global oil supplies, where six oil tankers have been damaged by explosions in the past six weeks.

Iran has denied involvement in the tanker attacks, but global jitters about a new Middle East conflagration disrupting oil exports have triggered a jump in crude prices.

Saudi Arabia, Washington’s main Gulf ally, said Iran had created a grave situation with its “aggressive behavior” and the kingdom was consulting other Gulf Arab states on next steps.

Tensions with Iran flared with Trump’s withdrawal last year from a 2015 nuclear accord with Iran, and have worsened as Washington imposed fresh sanctions to throttle Tehran’s vital oil trade. Iran retaliated earlier this week with a threat to breach limits on its nuclear activities imposed by the deal.

The U.S. sanctions have hammered Iran’s economy, scuttling its oil exports and barring it from the dollar-dominated global finance system. That has undone the promise of trade rewards from the 2015 deal designed to curb its nuclear ambitions.

Iranian state media said the “spy” drone was brought down over the southern Iranian province of Hormozgan, which is on the Gulf, with a locally made 3 Khordad missile.

Lieutenant General Joseph Guastella, the top U.S. Air Force commander in the Middle East, told reporters the drone was shot down at high altitude about 34 km (21 miles) from the nearest point of land on the Iranian coast.

U.S. Central Command later posted a tweet here that included a map of what Guastella called the drone's flight path showing it WAS outside Iran's territorial waters. "This was an unprovoked attack on a U.S. surveillance asset that had not violated Iranian airspace at any time," he added.

Independent confirmation of the drone’s location when it was brought down was not immediately available.

The Trump administration is pursuing a campaign to isolate Iran and press it towards concessions on its nuclear and missile programs and involvement in regional conflicts.

Washington said on Monday it would deploy about 1,000 more troops, along with Patriot missiles and manned and unmanned surveillance aircraft, to the Middle East on top of a 1,500-troop increase announced after attacks on Gulf tankers in May.

Trump has dispatched forces including aircraft carriers, B-52 bombers and troops over the past few weeks. Iran said last week it was responsible for the security of the Strait of Hormuz, calling on American forces to leave the Gulf.

In the United States, House of Representatives Speaker Nancy Pelosi, the top Democrat in Congress, said Washington had no appetite for war with Iran and should “do everything in our power to de-escalate.”

After a White House briefing for lawmakers, Democratic Senate Minority Leader Chuck Schumer, told reporters he was worried Trump “may bumble into a war”. Schumer said he and his fellow Democrats believed congressional approval was needed to fund any conflict with Iran.

But Trump’s fellow Republican, Senate Majority Leader Mitch McConnell, told reporters: “The administration is engaged in what I called measured responses.”

While U.S. rhetoric against Iran has sharped, European states - fellow signatories of the nuclear deal with Iran - have been more cautious, saying more evidence is needed to pinpoint responsibility for the tanker strikes.

They have sought to keep the nuclear deal alive despite the U.S. pullout, but Tehran has told them and other world powers who signed the accord that they must rein in Trump’s aggressive stance towards Iran or it too will bow out of the deal. </s> WASHINGTON — A U.S. official said the military made preparations Thursday night for limited strikes on Iran in retaliation for the downing of a U.S. surveillance drone, but approval was abruptly withdrawn before the attacks were launched.

The official, who was not authorized to discuss the operation publicly and spoke on condition of anonymity, said the targets would have included radars and missile batteries.

The New York Times reported that President Donald Trump had approved the strikes, but then called them off. The newspaper cited anonymous senior administration officials.

The White House on Thursday night declined requests for information about whether Trump changed his mind.

According to the official who spoke to the AP, the strikes were recommended by the Pentagon and were among the options presented to senior administration officials.

It was unclear how far the preparations had gone, but no shots were fired or missiles launched.

The military operation was called off around 7:30 p.m. Washington time, after Trump had spent most of Thursday discussing Iran strategy with top national security advisers and congressional leaders.

Asked earlier in the day about a U.S. response to the attack, he said, “You’ll soon find out.”

Trump declared that “Iran made a very big mistake” by shooting down the U.S. drone over the Strait of Hormuz. But he also suggested that shooting down the drone was a foolish error rather than an intentional escalation of the tensions that have led to rising fears of open military conflict.

“I find it hard to believe it was intentional, if you want to know the truth,” Trump said at the White House. “I think that it could have been somebody who was loose and stupid that did it.”

On Capitol Hill, leaders urged caution to avoid escalation, and some lawmakers insisted the White House must consult with Congress before taking any actions.

Secretary of State Mike Pompeo and national security adviser John Bolton have advocated hardline policies against Iran, but Rep. Adam Schiff, the chairman of the House intelligence committee, said “the president certainly was listening” when congressional leaders at the meeting urged him to be cautious and not escalate the already tense situation.

House Speaker Nancy Pelosi said no specific options for a U.S. response were presented at the more than hour-long meeting. Senate Majority Leader Mitch McConnell said, “The administration is engaged in what I would call measured responses.” And late Thursday, House Republicans on the Foreign Affairs, intelligence and Armed Services committees issued a statement using the same word, saying, “There must be a measured response to these actions.”

The downing of the huge, unmanned aircraft , which Iran portrayed as a deliberate defense of its territory rather than a mistake, was a stark reminder of the risk of military conflict between U.S. and Iranian forces as the Trump administration combines a “maximum pressure” campaign of economic sanctions with a buildup of American forces in the region. </s> President Donald Trump on Friday described a nail-biting decision to call off an imminent attack on Iran in order to avoid disproportionate casualties, but the account is already facing scrutiny from aides around him and military analysts questioning the sequence of events he laid out in tweets and statements.

Early in the day, the president said he called off the counterattack at the last minute because it would kill 150 people in retaliation for the downing of an unmanned surveillance drone. “We were cocked & loaded to retaliate last night on 3 different sights when I asked, how many will die,” he tweeted.

But administration officials said Trump was told earlier Thursday how many casualties could occur if a strike on Iran was carried out, and that he had given the green light to prepare for the operation Thursday morning.

The confusion reinforced concerns about the Trump administration’s credibility at a time when key U.S. allies are already questioning its narrative about Iran’s culpability for a recent spate of attacks on oil tankers.

The decision has divided his top advisers with senior Pentagon officials opposing the decision to strike and national security adviser John Bolton strongly supporting it.

Iran said Friday that the United States had “no justification” for a retaliatory strike and vowed to respond “firmly” to any U.S. military action.

Trump’s morning tweets appeared to gloss over the fact that he was the one, as commander in chief, who had ordered the retaliation against Iran in the first place.

Trump administration officials, who like others spoke on the condition of anonymity to discuss sensitive national security decisions, said the president approved the strikes after Iran’s Islamic Revolutionary Guard Corps earlier in the day shot down the Navy RQ-4 Global Hawk, a move Trump described as a “very big mistake.”

But he later changed his mind, the officials said.

The commander of the Revolutionary Guard’s aerospace division said Friday that Iran had sent “warnings” to the drone before shooting it down. In an interview with Iran’s state-controlled broadcaster, Brig. Gen. Amir Ali Hajizadeh said a final warning was sent at 3:55 a.m. local time Thursday.

“When it did not redirect its route and continued flying toward and into our territory, we had to shoot it at 4:05 a.m.,” he said. “Our national security is a red line.”

He said Iran refrained from also shooting down a U.S. P-8 patrol aircraft, with 35 people on board, that he asserted had accompanied the drone into Iranian airspace. His claim could not immediately be verified.

A senior U.S. defense official said Friday morning that the Pentagon had Navy assets poised to strike in Iran if directed, including ships accompanying the aircraft carrier USS Abraham Lincoln. Those attacks could have included airstrikes with jets, or — more likely — Tomahawk cruise missiles, the official said.

Trump’s initial tweets suggested that he had canceled his own order: “10 minutes before the strike I stopped it,” he said. But in an interview with NBC’s Chuck Todd for “Meet the Press,” the president said he hadn’t given final approval to any strikes and that no planes were in the air.

“Nothing was green lighted until the very end because things change,” Trump said in the interview.

In his Twitter posts Friday morning, Trump wrote that “sanctions are biting & more added last night.” However, the Treasury Department did not add any new sanctions against Iran on Thursday night.

There was also confusion about how the United States and Iran were communicating during the crisis at a time when the two adversaries have very few diplomatic contacts.

The Reuters news agency reported Friday that Iranian officials said they received a message from Trump through Oman overnight warning that a U.S. attack was imminent.

When asked about the report, a senior U.S. administration official said the United States never sent a message to Iran via the Omanis. The country at the eastern corner of the Arabian Peninsula has long been an interlocutor between the West and Iran, but not on this occasion, the official said.

“It is a complete lie and propaganda from Iran,” the official said.

Earlier Friday, the head of Iranian media services also told NBC News that the Reuters report was inaccurate. He said such a message from the United States was never sent and the content of the messages is also false.

The Federal Aviation Administration late Thursday barred U.S.-registered aircraft from operating over the Persian Gulf and Gulf of Oman, due to an increase in military activities and political tensions that it said might “place commercial flights at risk.”

Several U.S. and international carriers said that they had either canceled flights over Iranian airspace or were taking steps to avoid the Strait of Hormuz.

The day’s events have left lawmakers in both parties confused about whether the United States remains on the precipice of a military conflict or if an imminent crisis had been averted.

House Speaker Nancy Pelosi, D-Calif., said Friday that she was not informed of Trump’s plans to strike Iran but described the latest events as a “dangerous, high-tension situation.”

While Senate Majority Leader Mitch McConnell, R-Ky., expressed confidence in the president, several hawks in Congress said the only appropriate response would be a swift military counter-strike.

“They’re trying to break our will and intimidate us to come to the negotiating table,” Sen. Lindsey Graham, R-S.C., said of the Iranians.

Trump’s comments on Thursday also left room for questions about how his administration planned to respond to Iran. Immediately following the drone’s downing, he tweeted that “Iran made a mistake.”

But Trump said he found it “hard to believe” that the attack on the drone “was intentional” on the part of Iran’s top officials. He also noted that the aircraft was unmanned. “There was no man or woman in it,” he said. “It would have made a big difference” if a plane carrying people had been shot down. “It would have made a big, big difference.”

Iran’s strike on the U.S. drone Thursday followed a number of recent incidents, including attacks on tankers, that American officials have depicted as part of an Iranian effort to hurt the United States and its allies in the region. The United States has continued its “maximum pressure” campaign against a country the Trump administration has identified as its main adversary in the Middle East.

Tehran has responded with defiance to the campaign, which was launched after Trump withdrew the United States from the 2015 Iran nuclear deal and has included designating the Revolutionary Guard as a terrorist group and taking steps to cut off Iranian oil sales.

On Thursday, the European Union said officials from Germany, Britain, France, Russia, China and Iran would meet next week to discuss strategies to salvage the nuclear pact despite renewed U.S. sanctions and Tehran’s threat to exceed limits on its uranium stockpiles.

Saudi Arabia’s deputy defense minister said Friday on Twitter that he met with Brian Hook, the State Department’s special representative for Iran, in Riyadh “to explore the latest efforts to counter hostile Iranian acts.”

Hook called Friday for measures to “de-escalate” the tense situation with Iran. He told a news conference in the Saudi capital, “Our diplomacy does not give Iran the right to respond with military force; Iran needs to meet our diplomacy with diplomacy and not military force,” Reuters reported. “It’s important we do everything we can to de-escalate.”

The Revolutionary Guard’s top commander, Maj. Gen. Hossein Salami, called the downing of the drone “a clear message to America.”

The done incident occurred the week after two tankers, one Japanese and one Norwegian, were attacked in the Gulf of Oman. The Trump administration has blamed Iran for both incidents, at least one of which is said to have been carried out by use of limpet mine similar to devices previously displayed at Iranian military parades. Iran has denied involvement, calling the accusation “a lie.”

The tanker incidents were similar to an attack on a tanker off the United Arab Emirates in May. The U.S. military also accused Iran of firing a modified SA-7 surface-to-air missile at an MQ-9 Reaper drone over the Gulf of Oman as it surveilled the attack on the Japanese ship.

Also this month, Centcom said Houthi rebels shot down an MQ-9 over Yemen using an SA-6 surface-to-air missile in an attack that “was enabled by Iranian assistance.”

The latest incident came just days before acting defense secretary Patrick Shanahan was due to step down. Shanahan, who this week withdrew from his confirmation process after news media, including The Washington Post, published reports about past family strife, is handing responsibility for the military to Mark Esper, who now serves as Army secretary.

It is unclear how the turnover at the top of the Pentagon will affect an internal debate about how to respond to what officials say is an attempt to strike American interests. Some defense officials have voiced concerns that officials led by national security adviser John Bolton, who has publicly advocated regime change in Iran in the past, may be creating conditions in which war is inevitable.

Trump has previously authorized targeted strikes in the Middle East, including on government-controlled air bases in Syria. He was elected in 2016 promising to end American involvement in conflicts in the region.

At the same time, the Pentagon remains concerned about the potential for Iranian attacks on U.S. military personnel, especially those stationed in Iraq. During a visit to Baghdad last month, Secretary of State Mike Pompeo sought to relay a message for Iranian leaders that even one American death would result in a U.S. counterattack.

A U.S. official, speaking on the condition of anonymity, said U.S. naval assets were trying to recover pieces of the drone.

The strike on the RQ-4 is much more significant than the recent attacks on Reapers. Each Global Hawk, which has a wingspan of 131 feet, is worth more than $100 million and is packed with sensors and able to fly at altitudes of more than 55,000 feet to observe broad areas for periods that can stretch longer than a day.

The Global Hawk downed on Thursday was an older “demonstrator” model, according to another U.S. official, that had been transferred from the Air Force to the Navy to carry out a mission known as Broad Area Maritime Surveillance. The Pentagon has since begun testing a newer cousin, the MQ-4C Triton. Neither version carries weapons.

Hudson and Ryan reported from Washington. Cunningham reported from Dubai. The Washington Post’s Josh Dawsey, Dan Lamothe, William Branigin, Damian Paletta, and Karoun Demirjian in Washington contributed to this report. </s> Trump confirms he called off attack on Iran, citing potential casualties

DUBAI, United Arab Emirates - President Donald Trump ordered an attack on Iran on Thursday in retaliation for the downing of a surveillance drone in the Strait of Hormuz but called the operation off just before it was due to occur because it would have caused extensive casualties, he said Friday.

In a series of morning tweets, Trump said he called off strikes on three Iranian sites minutes before they were to be launched because he was informed of the likely loss of life among Iranians.

"We were cocked & loaded to retaliate last night on 3 different sights when I asked, how many will die," Trump tweeted. "150 people, sir, was the answer from a General. 10 minutes before the strike I stopped it."

Such a death toll was "not proportionate to shooting down an unmanned drone," Trump wrote, adding: "I am in no hurry, our Military is rebuilt, new, and ready to go, by far the best in the world. Sanctions are biting & more added last night. Iran can NEVER have Nuclear Weapons, not against the USA, and not against the WORLD!"

Iran said Friday the United States had "no justification" for a retaliatory strike and vowed to respond "firmly" to any U.S. military action.

Trump administration officials, who spoke on the condition of anonymity to discuss sensitive national security decisions, said the president approved the strikes after Iran's Islamic Revolutionary Guard Corps earlier in the day shot down a Navy RQ-4 Global Hawk operating off Iran's southern coast, a move Trump described as a "very big mistake."

But he later changed his mind, the officials said. The decision was first reported by the New York Times.

Trump's Friday morning tweets appeared to gloss over the fact that he was the one, as commander in chief, who had ordered the retaliatory strike against Iran in the first place.

The commander of the Revolutionary Guard's aerospace division said Friday that Iran had sent "warnings" to the drone before shooting it down. In an interview with Iran's state-controlled broadcaster, Brig. Gen. Amir Ali Hajizadeh said a final warning was sent at 3:55 a.m. local time Thursday.

"When it did not redirect its route and continued flying toward and into our territory, we had to shoot it at 4:05 a.m.," he said. "Our national security is a red line."

He also said that a U.S. P-8 patrol aircraft, with 35 people on board, had accompanied the drone into Iranian airspace. His claim could not immediately be verified.

"We could have downed it, too," Hajizadeh said of the plane, the Fars News Agency reported. "But we did not do it."

Iranian state television Friday published images that it said showed pieces of the drone recovered from the debris field. The photographs, which showed large fragments of what appeared to be an aircraft, could not be independently authenticated.

Iranian officials told the Reuters news agency Friday that Tehran received a message from Trump through Oman overnight warning that a U.S. attack was imminent.

"Trump said he was against any war with Iran and wanted to talk to Tehran about various issues," Reuters quoted one official as saying. "He gave a short period of time to get our response." The official added that it was up to Iran's supreme leader, Ayatollah Ali Khamenei, to decide whether to respond.

Iran's permanent mission to the United Nations did not immediately reply to request for comment.

The Federal Aviation Administration late Thursday barred U.S.-registered aircraft from operating over the Persian Gulf and Gulf of Oman, due to an increase in military activities and political tensions that it said might "place commercial flights at risk."

Several U.S. and international carriers said that they had either canceled flights over Iranian airspace or were taking steps to avoid the Strait of Hormuz.

The aborted operation to strike Iran capped a day in which news of the drone's downing heaped fuel on already heightened fears that the United States and Iran were on a course toward a military conflict as each side blamed the other for the incident.

Tehran and Washington gave conflicting accounts of what occurred when the drone with an airliner's wingspan crashed into the sea. While Iran said the aircraft had entered its airspace, the U.S. Central Command denied that assertion, characterizing the incident as an "unprovoked attack" over one of the world's most important commercial waterways.

In remarks alongside visiting Canadian Prime Minister Justin Trudeau at the White House, Trump condemned the shoot-down but also appeared to tamp down speculation that a counterstrike might be in the works, saying the drone may have been shot down without the knowledge of Iranian leaders.

"I'm not just talking about the country made a mistake. I'm talking about somebody under the command of that country made a mistake," Trump said at the White House. "I find it hard to believe it was intentional" on the part of Iran's top officials, the president said.

Trump was noncommittal about a U.S. counterattack. "Let's see what happens," he said. "This is a new fly in the ointment - what happened, shooting down the drone - and this country will not stand for it."

The White House invited a bipartisan group of top congressional leaders to a meeting Thursday afternoon to discuss the situation.

Among those invited were Senate Majority Leader Mitch McConnell, R-Ky., House Speaker Nancy Pelosi, D-Calif., Senate Minority Leader Chuck Schumer, D-N.Y., House Minority Leader Kevin McCarthy, R-Calif., and the chairmen and ranking minority party members of the House and Senate Intelligence and Armed Services committees.

"We had a good briefing," McConnell said, adding that he could confirm that an unmanned aerial vehicle "was fired on from Iranian soil and it was in international waters. And beyond that I think the administration is engaged in what I would call measured responses."

Schumer said he cautioned that "these conflicts have a way of escalating."

"The president may not intend to go to war here, but we're worried that he and the administration may bumble into a war," he said. "One of the best ways to avoid bumbling into war, a war that nobody wants, is to have a robust open debate and for Congress to have a real say. We learned that lesson in the run-up to Iraq" in 2003.

After the White House meeting, Pelosi held a closed-door session with Democratic lawmakers to brief them on the developments. "We know that the high-tension wires are up there, and we must do everything we can not to escalate the situation, but also to make sure that our personnel in the region are safe," she said.

Thursday's strike followed a number of recent incidents, including attacks on oil tankers, that American officials have depicted as part of an Iranian effort to hurt the United States and its allies in the region. The United States has continued its "maximum pressure" campaign against a country the Trump administration has identified as its main adversary in the Middle East.

Tehran has responded with defiance to the campaign, which was launched after Trump withdrew the United States from the 2015 Iran nuclear deal and has included designating the Revolutionary Guard as a terrorist group and taking steps to cut off Iranian oil sales.

On Thursday, the European Union said officials from Germany, Britain, France, Russia, China and Iran would meet next week to discuss strategies to salvage the nuclear pact despite renewed U.S. sanctions and Tehran's threat to exceed limits on its uranium stockpiles.

Saudi Arabia's deputy defense minister said Friday on Twitter that he met with Brian Hook, the State Department's special representative for Iran, in Riyadh "to explore the latest efforts to counter hostile Iranian acts."

The Revolutionary Guard's top commander, Maj. Gen. Hossein Salami, called the downing of the drone "a clear message to America."

"Our borders are Iran's red line, and we will react strongly against any aggression," Salami said in remarks carried by Iranian state television. "Iran is not seeking war with any country, but we are fully prepared to defend Iran."

Nearly a quarter of the world's traded oil passes through the Strait of Hormuz, which connects Middle East energy producers to markets around the globe.

Lt. Gen. Joseph Guastella, head of U.S. air forces in the Middle East, told reporters at the Pentagon that the Global Hawk was flying at high altitude in the vicinity of recent tanker attacks and was not at any time any closer than 21 miles to the nearest point on Iran's coast.

Guastella said the aircraft did not leave international airspace and was brought down by a Republican Guard surface-to-air missile fired from an area close to Goruk, Iran.

"This dangerous and escalatory attack was irresponsible and occurred in the vicinity of established air corridors between Dubai, UAE, and Muscat, Oman, possibly endangering innocent civilians," he said. Guastella did not take questions, and the Pentagon did not make anyone else available to discuss the tensions.

The Global Hawk incident occurred the week after two tankers, one Japanese and one Norwegian, were attacked in the Gulf of Oman. The Trump administration has blamed Iran for both incidents, at least one of which is said to have been carried out by use of limpet mine similar to devices previously displayed at Iranian military parades. Iran has denied involvement, calling the accusation "a lie."

The tanker incidents were similar to an attack on a tanker off the United Arab Emirates in May. The U.S. military also accused Iran of firing a modified SA-7 surface-to-air missile at an MQ-9 Reaper drone over the Gulf of Oman as it surveilled the attack on the Japanese ship.

Also this month, Centcom said Houthi rebels shot down an MQ-9 over Yemen using an SA-6 surface-to-air missile in an attack that "was enabled by Iranian assistance."

The latest incident came just days before acting defense secretary Patrick Shanahan was due to step down. Shanahan, who this week withdrew from his confirmation process after news media, including The Washington Post, published reports about past family strife, is handing responsibility for the military to Mark Esper, who now serves as Army secretary.

It is unclear how the turnover at the top of the Pentagon will affect an internal debate about how to respond to what officials say is an attempt to strike American interests. Some defense officials have voiced concerns that officials led by national security adviser John Bolton, who has publicly advocated regime change in Iran in the past, may be creating conditions in which war is inevitable.

Trump has previously authorized targeted strikes in the Middle East, including on government-controlled air bases in Syria. He was elected in 2016 promising to end American involvement in conflicts in the region.

At the same time, the Pentagon remains concerned about the potential for Iranian attacks on U.S. military personnel, especially those stationed in Iraq. During a visit to Baghdad last month, Secretary of State Mike Pompeo sought to relay a message for Iranian leaders that even one American death would result in a U.S. counterattack.

Trump appeared to tamp down the likelihood of an immediate military response as he highlighted the fact that the Global Hawk was unmanned. "We had nobody in the drone," he said. "It would have made a big difference, let me tell you."

Sen. Lindsey Graham, R-S.C., tweeted, "When it comes to the Middle East, there are seldom good choices."

"But in some instances, failing to act can prove to be the most dangerous choice of all," he said.

A U.S. official, speaking on the condition of anonymity, said U.S. naval assets were trying to recover pieces of the drone.

The strike on the RQ-4 is much more significant than the recent attacks on Reapers. Each Global Hawk, which has a wingspan of 131 feet, is worth more than $100 million and is packed with sensors and able to fly at altitudes of more than 55,000 feet to observe broad areas for periods that can stretch longer than a day.

The Global Hawk downed on Thursday was an older "demonstrator" model, according to another U.S. official, that had been transferred from the Air Force to the Navy to carry out a mission known as Broad Area Maritime Surveillance. The Pentagon has since begun testing a newer cousin, the MQ-4C Triton. Neither version carries weapons.

According to a Republican Guard statement, the U.S. drone took off from a base in the "southern Persian Gulf" and was heading toward Iran's Chabahar port "in full secrecy, violating the rules of international aviation."

"While returning to the western Hormuz Strait's region, the drone violated Iran's airspace and engaged in information-gathering and spying," the statement said.

At its narrowest, the Strait of Hormuz is just 21 nautical miles wide, and ships passing through it must enter the territorial waters of Iran and Oman. Under the rule of the shah in 1959, Iran extended its territorial waters to 12 nautical miles and declared that it would recognize only "innocent passage" through the area, essentially excluding warships engaging in activities deemed hostile. Oman also claimed a 12-mile territorial limit in 1972 and later demanded that foreign warships obtain permission to pass through its waters.

The United States does not recognize any restrictions on transit through the strait. </s> Iran on Friday denied President Donald Trump's statement that a United States warship destroyed an Iranian drone near the Persian Gulf after it threatened the ship, an incident that marked a new escalation of tensions between the countries less than a month after Iran downed an American drone in the same waterway and Trump came close to retaliating with a military strike.

The Iranian military said all its drones had returned safely to their bases and denied there was any confrontation with a US vessel the previous day.

“We have not lost any drone in the Strait of Hormuz nor anywhere else,” tweeted Deputy Foreign Minister Abbas Araghchi.

The strait is at the mouth of the Persian Gulf and serves as the passageway for a fifth of all global crude exports; a clash there highlights the risk of war between Iran and the US.

Trump on Thursday said the USS Boxer took defensive action after an Iranian drone closed to within 1,000 yards of the warship and ignored multiple calls to stand down.

Trump blamed Iran for a “provocative and hostile” action and said the US responded in self-defence. Iran's foreign minister, Mohammad Javad Zarif, told reporters as he arrived for a meeting at the United Nations that “we have no information about losing a drone today".

After Trump pulled the US out of the Iran nuclear deal last year and imposed economic sanctions on Tehran, the Iranians have pushed back on the military front, shooting down a US drone on June 20.

Also in the past weeks, the Persian Gulf region has seen six attacks on oil tankers that the US has blamed on Iran, and a tense encounter between Iran's Revolutionary Guard and the British navy. Iran has denied involvement in the attacks or the British naval encounter.

The US has also sent thousands of additional troops and increased its security presence in the region.

Adding to the economic pressure on Tehran, the Treasury Department said on Thursday it was imposing sanctions on what it called a network of front companies and agents involved in helping Iran buy sensitive materials for its nuclear programme. It said the targeted individuals and entities are based in Iran, China and Belgium.

The Pentagon said Thursday's incident happened at 10am local time in international waters while the Boxer was transiting the waterway to enter the Persian Gulf. The Boxer is among several US Navy ships in the area, including the USS Abraham Lincoln, an aircraft carrier that has been operating in the nearby North Arabian Sea for weeks.

Neither Trump nor the Pentagon spelled out how the Boxer destroyed the drone. CNN reported that the ship used electronic jamming to bring it down rather than hitting it with a missile.

In Tehran, the semi-official Tasnim news agency quoted military spokesman Gen. Abolfazl Shekari as saying that “all Iranian drones that are in the Persian Gulf and the Strait of Hormuz, including the one which the US president mentioned, after carrying out scheduled identification and control missions, have returned to their bases.”

The Iranians and Americans have had close encounters in the Strait of Hormuz in the past, and it's not unprecedented for Iran to fly a drone near a US warship.

In December, about 30 Iranian Revolutionary Guard vessels trailed the USS John C. Stennis aircraft carrier and its strike group through the strait as Associated Press journalists on board watched. One small vessel launched what appeared to be a commercial-grade drone to film the US ships.

Other transits have seen the Iranians fire rockets away from American warships or test-fire their machine guns. The Guard's small fast boats often cut in front of the massive carriers, running dangerously close to running into them in “swarm attacks". The Guard boats are often armed with bomb-carrying drones and sea-to-sea and surface-to-sea missiles.

Thursday's incident was the latest in a series of events that raised US-Iran tensions since early May when Washington accused Tehran of threatening US forces and interests in Iraq and in the Gulf.

In response, the US accelerated the deployment of the Lincoln and its strike group to the Arabian Sea and deployed four B-52 long-range bombers to the Gulf state of Qatar. It has since deployed additional Patriot air defense missile batteries in the Gulf region.

Shortly after Iran shot down a U.S. Navy drone aircraft in June, Trump ordered a retaliatory military strike but called it off at the last moment, saying the risk of casualties was disproportionate to the downing by Iran, which did not cost any US lives.

Iran claimed the US drone violated its airspace; the Pentagon denied this.

Zarif said on Thursday that Iran and the US were only “a few minutes away from a war” after Iran downed the American drone. He spoke to US-based media on the sidelines of his visit to the UN.

“We live in a very dangerous environment,” he said. “The United States has pushed itself and the rest of the world into probably the brink of an abyss.”

Zarif blamed Washington for the escalation and said that the Trump administration was “trying to starve our people” and “deplete our treasury” through economic sanctions.

Earlier on Thursday, Iran said the Revolutionary Guard seized a foreign oil tanker and its crew of 12 for smuggling fuel out of the country, and hours later released video showing the vessel to be a United Arab Emirates-based ship that had vanished in Iranian waters over the weekend.

The announcement cleared up the fate of the missing ship but raised a host of other questions and heightened worries about the free flow of traffic in the Strait of Hormuz, one of the world's most critical petroleum shipping routes. One-fifth of global crude exports pass through the strait. </s> Donald Trump insisted Friday that reports of the U.S. Navy bringing down an Iranian drone in the Strait of Hormuz are accurate – despite the Islamic nation's denials.

'We shot it down,' the president told reporters in the Oval Office, adding that there is 'no doubt about it.'

Trump warned Tehran's mullahs that the U.S. military has 'the most deadly ships ever conceived.'

'And we hope for their sake they don't do anything foolish. If they do, they will pay a price like nobody's ever paid a price.'

National Security Advisor John Bolton said the identity of the drone's owners and operators was not a mystery.

'There’s no question that this was an Iranian drone,' Bolton announced.

The pair spoke at an event commemorating the 50th anniversary of the Apollo 11 moon landing mission.

Iran had accused the U.S. of taking out an American drones by mistake after Donald Trump said the Navy had destroyed an unmanned craft over the Strait of Hormuz.

Tehran's deputy foreign minister Abbas Araghchi declared that none of its drones had been destroyed, neither 'in the Strait of Hormuz nor anywhere else.'

'I am worried that USS Boxer has shot down their own UAS (Unmanned Aerial Systems) by mistake!' he tweeted on Friday.

That came after the president announced Thursday that an Iranian drone making 'provocative and hostile' maneuvers had been destroyed, in what the Pentagon later said was an electronic warfare attack.

Trump seemed to disagree on Friday, saying the U.S. 'shot it down.'

The Strait of Hormuz is a strategic bottleneck through which a fifth of the world's oil passes each day, and sits partially in Iranian waters.

The president on Thursday called the incident 'the latest of many provocative and hostile actions by Iran against vessels operating in international waters.'

Iranian armed forces spokesman Brigadier General Abolfazl Shekarchi also denied the claims Friday, saying: 'Despite Trump's baseless and delusional claims, all of [Iran's] drones... have safely returned to their bases.'

'There have been no reports of a confrontation with the American USS Boxer,' he claimed.

Iran's military recently shot down a U.S. drone that it said was flying in Iranian airspace, firing a strike with a surface-to-air missile.

President Trump called off a planned airstrike at the last moment, saying later that retaliating would have killed approximately 150 people on the ground.

Trump made his announcement Thursday at the beginning of a White House ceremony to mark the return of an American flag that flew from the stern of an American ship in the D-Day invasion.

An hour earlier he had told reporters at the end of a pohto-op with Dutch Prime Minister Mark Rutte that 'a big event just happened in Iran. A big event.'

The drone was downed in international waters, according to a Pentagon official.

The increased use of drones by Iran and its allies for surveillance and attacks across the Middle East is raising alarms in Washington, according to a Reuters report this week.

The U.S. believes Iran-linked militias in Iraq have recently increased their surveillance of American troops and bases in the country by using off-the-shelf, commercially available drones.

The disclosure comes at a time of heightened tensions with Iran and underscores the many ways in which Tehran and the forces it backs are increasingly relying on unmanned aerial vehicles (UAVs) in places like Yemen, Syria, the Strait of Hormuz and Iraq.

Beyond surveillance, Iranian drones can drop munitions and even carry out 'a kamikaze flight where they load it up with explosives and fly it into something,' according to a U.S. official who spoke to Reuters on condition of anonymity.

Iran now flies two or three drones over Gulf waters every day, the U.S. official estimated, making it a core part of Tehran's effort to monitor the Strait of Hormuz.

The United States and Saudi Arabia have accused Iran of carrying out attacks against six oil tankers near the Strait in the past two months, a claim Tehran has denied.

'We have seen an uptick in drone activity in Iraq near our bases and facilities,' the official said. 'Certainly the drones that we have seen are more of the commercial off-the-shelf variant. So they're obviously a deniable type UAV-activity in Iraq.'

In recent weeks, mortars and rockets have been fired at bases in Iraq where U.S. forces are located but no American troops have been injured.

Iraqi militia groups linked to Iran began using drones in 2014 and 2015 in battles to retake territory from ISIS.

These groups received training on the use of drones from members of Iran's Revolutionary Guards and Lebanon's Iranian-backed Hezbollah, according to Iraqi security officials with knowledge of militia activities.

'Key militia groups have the ability to launch aerial attacks using drones. Will they target American interests? That hasn't happened yet,' said one Iraqi security official.

'They used Katyusha and mortars in very restricted attacks against American interests in Iraq to send a message rather than trying to inflict damage. Using explosive-laden drones is very possible once we have a worsening situation between Tehran and Washington.'

In March, Iran boasted about a complex military exercise involving 50 drones. In a slickly edited video aired on state TV, waves of drones streak across a clear blue sky, bombing buildings on an island in the Gulf.

The show of force was intended to highlight Iran's locally developed UAV program, which it has been building up for several years.

U.S. forces shot down Iranian-made drones in 2017 in Syria, after deeming them a threat to both U.S.-backed forces and their advisers. </s> WASHINGTON (AP) — A U.S. warship on Thursday destroyed an Iranian drone in the Strait of Hormuz after it threatened the ship, President Donald Trump said. The incident marked a new escalation of tensions between the countries less than one month after Iran downed an American drone in the same waterway and Trump came close to retaliating with a military strike.

In remarks at the White House, Trump blamed Iran for a "provocative and hostile" action and said the U.S. responded in self-defense. Iran's foreign minister, Mohammad Javad Zarif, told reporters as he arrived for a meeting at the United Nations that "we have no information about losing a drone today."

Trump said the Navy's USS Boxer, an amphibious assault ship, took defensive action after the Iranian aircraft closed to within 1,000 yards of the ship and ignored multiple calls to stand down.

"The United States reserves the right to defend our personnel, facilities and interests and calls upon all nations to condemn Iran's attempts to disrupt freedom of navigation and global commerce," Trump said.

The Pentagon said the incident happened at 10 a.m. local time Thursday in international waters while the Boxer was transiting the waterway to enter the Persian Gulf. The Boxer is among several U.S. Navy ships in the area, including the USS Abraham Lincoln, an aircraft carrier that has been operating in the nearby North Arabian Sea for weeks.

"A fixed-wing unmanned aerial system approached Boxer and closed within a threatening range," chief Pentagon spokesman Jonathan Hoffman said in a written statement. "The ship took defensive action against the UAS to ensure the safety of the ship and its crew."

The Iranians and Americans have had close encounters in the Strait of Hormuz in the past, and it's not unprecedented for Iran to fly a drone near a U.S. warship.

In December, about 30 Iranian Revolutionary Guard vessels trailed the USS John C. Stennis aircraft carrier and its strike group through the strait as Associated Press journalists on board watched. One small vessel launched what appeared to be a commercial-grade drone to film the U.S. ships.

Other transits have seen the Iranians fire rockets away from American warships or test-fire their machine guns. The Guard's small fast boats often cut in front of the massive carriers, running dangerously close to running into them in "swarm attacks." The Guard boats are often armed with bomb-carrying drones and sea-to-sea and surface-to-sea missiles.

Thursday's incident was the latest in a series of events that raised U.S.-Iran tensions since early May when Washington accused Tehran of threatening U.S. forces and interests in Iraq and in the Gulf. In response, the U.S. accelerated the deployment of the Lincoln and its strike group to the Arabian Sea and deployed four B-52 long-range bombers to the Gulf state of Qatar. It has since deployed additional Patriot air defense missile batteries in the Gulf region.

Shortly after Iran shot down a U.S. Navy drone aircraft on June 20, Trump ordered a retaliatory military strike but called it off at the last moment, saying the risk of casualties was disproportionate to the downing by Iran, which did not cost any U.S. lives.

Iran claimed the U.S. drone violated its airspace; the Pentagon denied this.

Zarif said Thursday that Iran and the U.S. were only "a few minutes away from a war" after Iran downed the American drone. He spoke to U.S.-based media on the sidelines of a visit to the United Nations.

Zarif also blamed Washington for the escalation of tensions.

"We live in a very dangerous environment," he said. "The United States has pushed itself and the rest of the world into probably the brink of an abyss." Zarif accused the Trump administration of "trying to starve our people" and "deplete our treasury" through economic sanctions.

Earlier Thursday, Iran said its Revolutionary Guard seized a foreign oil tanker and its crew of 12 for smuggling fuel out of the country, and hours later released video showing the vessel to be a United Arab Emirates-based ship that had vanished in Iranian waters over the weekend.

The announcement cleared up the fate of the missing ship but raised a host of other questions and heightened worries about the free flow of traffic in the Strait of Hormuz, one of the world's most critical petroleum shipping routes. One-fifth of global crude exports passes through the strait. </s> DUBAI, United Arab Emirates -- President Donald Trump ordered an attack on Iran on Thursday in retaliation for the downing of a surveillance drone in the Strait of Hormuz but called the operation off just before it was due to occur because it would have caused extensive casualties, he said Friday.

In a series of morning tweets, Trump said he called off strikes on three Iranian sites minutes before they were to be launched because he was informed of the likely loss of life among Iranians.

"We were cocked & loaded to retaliate last night on 3 different sights when I asked, how many will die," Trump tweeted. "150 people, sir, was the answer from a General. 10 minutes before the strike I stopped it."

Such a death toll was "not proportionate to shooting down an unmanned drone," Trump wrote, adding: "I am in no hurry, our Military is rebuilt, new, and ready to go, by far the best in the world. Sanctions are biting & more added last night. Iran can NEVER have Nuclear Weapons, not against the USA, and not against the WORLD!"

Iran said Friday the United States had "no justification" for a retaliatory strike and vowed to respond "firmly" to any U.S. military action.

Trump administration officials, who spoke on the condition of anonymity to discuss sensitive national security decisions, said the president approved the strikes after Iran's Islamic Revolutionary Guard Corps earlier in the day shot down a Navy RQ-4 Global Hawk operating off Iran's southern coast, a move Trump described as a "very big mistake."

But he later changed his mind, the officials said. The decision was first reported by the New York Times.

The commander of the Revolutionary Guard's aerospace division said Friday that Iran had sent "warnings" to the drone before shooting it down. In an interview with Iran's state-controlled broadcaster, Brig. Gen. Amir Ali Hajizadeh said a final warning was sent at 3:55 a.m. local time Thursday.

"When it did not redirect its route and continued flying toward and into our territory, we had to shoot it at 4:05 a.m.," he said. "Our national security is a red line."

He also said that a U.S. P-8 patrol aircraft, with 35 people on board, had accompanied the drone into Iranian airspace. His claim could not immediately be verified.

"We could have downed it, too," Hajizadeh said of the plane, the Fars News Agency reported. "But we did not do it."

A senior U.S. defense official, speaking on the condition of anonymity due to the sensitivity of the subject, said Friday morning that the Pentagon had Navy assets poised to strike in Iran if directed, including ships accompanying the aircraft carrier USS Abraham Lincoln. Those attacks could have included airstrikes with jets, or - more likely - Tomahawk cruise missiles, the official said.

Among the ships that could have been involved were the guided-missile cruiser USS Leyte Gulf and the destroyer USS Bainbridge, the official said. Both vessels can carry Tomahawk missiles.

The official said he could not say whether Iran considered shooting down a Navy P-8 Poseidon surveillance plane with a few dozen U.S. service members aboard before ultimately striking an unmanned RQ-4 over the Gulf of Oman. However, the official said, a P-8 was flying in the region that night.

Iranian state television Friday published images that it said showed pieces of the drone recovered from the debris field. The photographs, which showed large fragments of what appeared to be an aircraft, could not be independently authenticated.

Iranian officials told the Reuters news agency Friday that Tehran received a message from Trump through Oman overnight warning that a U.S. attack was imminent.

"Trump said he was against any war with Iran and wanted to talk to Tehran about various issues," Reuters quoted one official as saying. "He gave a short period of time to get our response." The official added that it was up to Iran's supreme leader, Ayatollah Ali Khamenei, to decide whether to respond.

Iran's permanent mission to the United Nations did not immediately reply to request for comment.

The Federal Aviation Administration late Thursday barred U.S.-registered aircraft from operating over the Persian Gulf and Gulf of Oman, due to an increase in military activities and political tensions that it said might "place commercial flights at risk."

Several U.S. and international carriers said that they had either canceled flights over Iranian airspace or were taking steps to avoid the Strait of Hormuz.

The aborted operation to strike Iran capped a day in which news of the drone's downing heaped fuel on already heightened fears that the United States and Iran were on a course toward a military conflict as each side blamed the other for the incident.

Tehran and Washington gave conflicting accounts of what occurred when the drone with an airliner's wingspan crashed into the sea. While Iran said the aircraft had entered its airspace, the U.S. Central Command denied that assertion, characterizing the incident as an "unprovoked attack" over one of the world's most important commercial waterways.

In remarks alongside visiting Canadian Prime Minister Justin Trudeau at the White House, Trump condemned the shoot-down but also appeared to tamp down speculation that a counterstrike might be in the works, saying the drone may have been shot down without the knowledge of Iranian leaders.

"I'm not just talking about the country made a mistake. I'm talking about somebody under the command of that country made a mistake," Trump said at the White House. "I find it hard to believe it was intentional" on the part of Iran's top officials, the president said.

Trump was noncommittal about a U.S. counterattack. "Let's see what happens," he said. "This is a new fly in the ointment - what happened, shooting down the drone - and this country will not stand for it."

The White House invited a bipartisan group of top congressional leaders to a meeting Thursday afternoon to discuss the situation.

Among those invited were Senate Majority Leader Mitch McConnell, R-Ky., House Speaker Nancy Pelosi, D-Calif., Senate Minority Leader Chuck Schumer, D-N.Y., House Minority Leader Kevin McCarthy, R-Calif., and the chairmen and ranking minority party members of the House and Senate Intelligence and Armed Services committees.

"We had a good briefing," McConnell said, adding that he could confirm that an unmanned aerial vehicle "was fired on from Iranian soil and it was in international waters. And beyond that I think the administration is engaged in what I would call measured responses."

Schumer said he cautioned that "these conflicts have a way of escalating."

"The president may not intend to go to war here, but we're worried that he and the administration may bumble into a war," he said. "One of the best ways to avoid bumbling into war, a war that nobody wants, is to have a robust open debate and for Congress to have a real say. We learned that lesson in the run-up to Iraq" in 2003.

After the White House meeting, Pelosi held a closed-door session with Democratic lawmakers to brief them on the developments. "We know that the high-tension wires are up there, and we must do everything we can not to escalate the situation, but also to make sure that our personnel in the region are safe," she said.

Thursday's strike followed a number of recent incidents, including attacks on oil tankers, that American officials have depicted as part of an Iranian effort to hurt the United States and its allies in the region. The United States has continued its "maximum pressure" campaign against a country the Trump administration has identified as its main adversary in the Middle East.

Tehran has responded with defiance to the campaign, which was launched after Trump withdrew the United States from the 2015 Iran nuclear deal and has included designating the Revolutionary Guard as a terrorist group and taking steps to cut off Iranian oil sales.

On Thursday, the European Union said officials from Germany, Britain, France, Russia, China and Iran would meet next week to discuss strategies to salvage the nuclear pact despite renewed U.S. sanctions and Tehran's threat to exceed limits on its uranium stockpiles.

Saudi Arabia's deputy defense minister said Friday on Twitter that he met with Brian Hook, the State Department's special representative for Iran, in Riyadh "to explore the latest efforts to counter hostile Iranian acts."

The Revolutionary Guard's top commander, Maj. Gen. Hossein Salami, called the downing of the drone "a clear message to America."

"Our borders are Iran's red line, and we will react strongly against any aggression," Salami said in remarks carried by Iranian state television. "Iran is not seeking war with any country, but we are fully prepared to defend Iran."

Nearly a quarter of the world's traded oil passes through the Strait of Hormuz, which connects Middle East energy producers to markets around the globe.

Lt. Gen. Joseph Guastella, head of U.S. air forces in the Middle East, told reporters at the Pentagon that the Global Hawk was flying at high altitude in the vicinity of recent tanker attacks and was not at any time any closer than 21 miles to the nearest point on Iran's coast.

Guastella said the aircraft did not leave international airspace and was brought down by a Republican Guard surface-to-air missile fired from an area close to Goruk, Iran.

"This dangerous and escalatory attack was irresponsible and occurred in the vicinity of established air corridors between Dubai, UAE, and Muscat, Oman, possibly endangering innocent civilians," he said. Guastella did not take questions, and the Pentagon did not make anyone else available to discuss the tensions.

The Global Hawk incident occurred the week after two tankers, one Japanese and one Norwegian, were attacked in the Gulf of Oman. The Trump administration has blamed Iran for both incidents, at least one of which is said to have been carried out by use of limpet mine similar to devices previously displayed at Iranian military parades. Iran has denied involvement, calling the accusation "a lie."

The tanker incidents were similar to an attack on a tanker off the United Arab Emirates in May. The U.S. military also accused Iran of firing a modified SA-7 surface-to-air missile at an MQ-9 Reaper drone over the Gulf of Oman as it surveilled the attack on the Japanese ship.

Also this month, Centcom said Houthi rebels shot down an MQ-9 over Yemen using an SA-6 surface-to-air missile in an attack that "was enabled by Iranian assistance."

The latest incident came just days before acting defense secretary Patrick Shanahan was due to step down. Shanahan, who this week withdrew from his confirmation process after news media, including The Washington Post, published reports about past family strife, is handing responsibility for the military to Mark Esper, who now serves as Army secretary.

It is unclear how the turnover at the top of the Pentagon will affect an internal debate about how to respond to what officials say is an attempt to strike American interests. Some defense officials have voiced concerns that officials led by national security adviser John Bolton, who has publicly advocated regime change in Iran in the past, may be creating conditions in which war is inevitable.

Trump has previously authorized targeted strikes in the Middle East, including on government-controlled air bases in Syria. He was elected in 2016 promising to end American involvement in conflicts in the region.

At the same time, the Pentagon remains concerned about the potential for Iranian attacks on U.S. military personnel, especially those stationed in Iraq. During a visit to Baghdad last month, Secretary of State Mike Pompeo sought to relay a message for Iranian leaders that even one American death would result in a U.S. counterattack.

Trump appeared to tamp down the likelihood of an immediate military response as he highlighted the fact that the Global Hawk was unmanned. "We had nobody in the drone," he said. "It would have made a big difference, let me tell you."

Sen. Lindsey Graham, R-S.C., tweeted, "When it comes to the Middle East, there are seldom good choices."

"But in some instances, failing to act can prove to be the most dangerous choice of all," he said.

A U.S. official, speaking on the condition of anonymity, said U.S. naval assets were trying to recover pieces of the drone.

The strike on the RQ-4 is much more significant than the recent attacks on Reapers. Each Global Hawk, which has a wingspan of 131 feet, is worth more than $100 million and is packed with sensors and able to fly at altitudes of more than 55,000 feet to observe broad areas for periods that can stretch longer than a day.

The Global Hawk downed on Thursday was an older "demonstrator" model, according to another U.S. official, that had been transferred from the Air Force to the Navy to carry out a mission known as Broad Area Maritime Surveillance. The Pentagon has since begun testing a newer cousin, the MQ-4C Triton. Neither version carries weapons.

According to a Revolutionary Guard statement, the U.S. drone took off from a base in the "southern Persian Gulf" and was heading toward Iran's Chabahar port "in full secrecy, violating the rules of international aviation."

"While returning to the western Hormuz Strait's region, the drone violated Iran's airspace and engaged in information-gathering and spying," the statement said.

At its narrowest, the Strait of Hormuz is just 21 nautical miles wide, and ships passing through it must enter the territorial waters of Iran and Oman. Under the rule of the shah in 1959, Iran extended its territorial waters to 12 nautical miles and declared that it would recognize only "innocent passage" through the area, essentially excluding warships engaging in activities deemed hostile. Oman also claimed a 12-mile territorial limit in 1972 and later demanded that foreign warships obtain permission to pass through its waters.

The United States does not recognize any restrictions on transit through the strait.

Ryan and Lamothe reported from Washington. The Washington Post’s William Branigin in Washington contributed to this report.
Trump administration officials say that President Donald Trump ordered the United States Armed Forces to conduct military strikes against targets of the Armed Forces of the Islamic Republic of Iran in retaliation for downing an American surveillance drone the day prior, and that he changed his mind hours later and ordered an immediate stop to the operation while American warplanes were in the air and warships were in position.