President Donald Trump has condemned the "heinous" suspected poison gas attack in Syria and said he'll make a decision on the U.S. response within 24 to 48 hours.

Speaking in the White House Cabinet Room Monday, Trump vowed to find out who is responsible for the attack that reportedly killed at least 40 people.

Trump said during a Cabinet meeting with reporters that, "If it's Russia, if it's Syria, if it's Iran, if it's all of them together, we'll figure it out."

Opposition activists said 40 people died in the chemical attack late Saturday in the suburbs of the Syrian capital and blamed it on the Syrian government, which is closely allied with Russia.

Syria has blamed Israel for a missile attack on a central air base early Monday that reportedly killed 14 people, including three Iranians.

Since 2012, Israel has struck inside Syria more than 100 times, mostly targeting suspected weapons’ convoys destined for the Lebanese militant group Hezbollah, which has been fighting alongside Syrian government forces.

Most recently, Israel hit the same T4 base in February, after it said an Iranian drone that had violated Israeli airspace took off from the base. The base, which was used as a launching pad for counter offensive attacks against Islamic State militants who were at one point stationed close by, is near the Shayrat air base, which was targeted by U.S. missiles last year in response to a chemical weapons attack.

Israel’s foreign ministry had no comment when asked about the accusations.

Rami Abdurrahman, the Observatory’s chief, said the assault targeted a mobile air defense unit and some buildings inside the air base. He added that it also hit posts outside the base used by the Iranians and Iran-backed fighters.

Israel fears Iran could use Syria’s territory to stage attacks on it. The U.S. launched several dozen Tomahawk cruise missiles at a Syrian air base last year, after a chemical attack in the northern Syrian town of Khan Sheikhoun killed dozens of people.

Saturday’s suspected poison gas attack on the besieged town of Douma came almost exactly a year after the U.S. missile attack prompted by the Khan Sheikhoun deaths.

In response to the reports, President Trump on Sunday blamed Syrian government forces for what he called a “mindless CHEMICAL attack.” In a series of tweets, President Trump held Russia and Iran, Syrian President Bashar Assad’s chief sponsors, responsible.

The Syrian government denied the chemical weapons allegations, calling them fabrications.

First responders entering apartments in Douma late Saturday said they found bodies collapsed on floors, some foaming at the mouth. The opposition’s Syrian Civil Defense rescue organization said the victims appeared to have suffocated.

The organization, also known as the White Helmets, and the Syrian American Medical Society, a medical relief organization, did not identify the substance used but said survivors treated at clinics smelled strongly of chlorine.

Those reports could not be independently verified because of a government blockade around the town.

Hours after the attack, the Army of Islam rebel group agreed to surrender the town and evacuate their fighters to rebel-held northern Syria, Syrian state media reported. The group also agreed to give up its prisoners, a key government demand.

The government agreed to halt its assault after three days of indiscriminate air and ground attacks.

More than 100 buses entered the town on Sunday night to take the fighters and their families to Jarablus, a town under the shared control of rebels and Turkey, said Syrian state-affiliated al-Ikhbariya TV.

Syrian state TV said two buses left early Monday and that 11 more buses were getting ready to move.

Syrian state media said dozens of civilians who had been held for years by the rebels were set free. The SANA news agency said the people were freed around midnight on SundayPresident , adding that they had been held by the Army of Islam group since 2013.

The evacuations follow a pattern of departures around the capital, Damascus, and other major Syrian cities as the government reasserts its control after seven years of war.

Human rights groups and U.N. officials say the tactic amounts to forced displacement, a war crime. The U.N. Security Council planned to hold an emergency meeting Monday to discuss the chemical attack.

In his tweets Sunday, President Trump called Assad an “animal” and delivered a rare personal criticism of Russian President Vladimir Putin for supporting him. President Trump has declared his intent to withdraw U.S. troops from Syria in the coming months, despite resistance from many of his advisers.

Syrian rescuers from the White Helmets documented 42 fatalities in Saturday’s reported chemical attack but were impeded from searching further by strong odors that caused breathing difficulties, said Siraj Mahmoud, a spokesman for the group.

More than 500 people, mostly women and children, were brought to medical centers complaining of difficulties breathing, foaming at the mouth and burning sensations in the eyes. Some had bluish skin, a sign of oxygen deprivation, according to a statement, symptoms consistent with chemical exposure.

The Observatory gave a higher death toll, saying at least 80 people were killed in Douma, including around 40 who died from suffocation. But it said the suffocations were the result of shelters collapsing on people inside them.

In denying the chemical weapons allegations, a government statement said “the army, which is advancing rapidly and with determination, does not need to use any kind of chemical agents.”

Russia denied any involvement in the attack. Maj. Gen. Yuri Yevtushenko was quoted by Russian news agencies Sunday as saying Russia was prepared to send specialists to Douma to “confirm the fabricated nature” of the reports.

In recent weeks, government forces have recaptured villages and towns in the eastern Ghouta suburbs of the capital. Douma was the only town left holding out.

A 2013 chemical attack in eastern Ghouta that killed hundreds of people was widely blamed on government forces. The U.S. threatened military action but later backed down.

Syria denies ever using chemical weapons during the war and says it eliminated its chemical arsenal under a 2013 agreement brokered by the U.S. and Russia.</s>Israel fears Iran could use Syria's territory to stage attacks on it. The U.S. launched several dozen Tomahawk cruise missiles at a Syrian air base last year, after a chemical attack in the northern Syrian town of Khan Sheikhoun killed dozens of people.

Saturday's suspected poison gas attack on the besieged town of Douma came almost exactly a year after the U.S. missile attack prompted by the Khan Sheikhoun deaths.

In response to the reports, Trump on Sunday blamed Syrian government forces for what he called a "mindless CHEMICAL attack." In a series of tweets, Trump held Russia and Iran, Syrian President Bashar Assad's chief sponsors, responsible.

Trump was to meet with his senior military leadership on Monday, the same day his new national security adviser, John Bolton, assumes his post. Bolton has previously advocated significant airstrikes against Syria.

The Syrian government denied the chemical weapons allegations, calling them fabrications.

First responders entering apartments in Douma late Saturday said they found bodies collapsed on floors, some foaming at the mouth. The opposition's Syrian Civil Defence rescue organization said the victims appeared to have suffocated.

The organization, also known as the White Helmets, and the Syrian American Medical Society, a medical relief organization, did not identify the substance used but said survivors treated at clinics smelled strongly of chlorine.

Those reports could not be independently verified because of a government blockade around the town.

Hours after the attack, the Army of Islam rebel group agreed to surrender the town and evacuate their fighters to rebel-held northern Syria, Syrian state media reported. The group also agreed to give up its prisoners, a key government demand.

The government agreed to halt its assault after three days of indiscriminate air and ground attacks.

More than 100 buses entered the town on Sunday night to take the fighters and their families to Jarablus, a town under the shared control of rebels and Turkey, said Syrian state-affiliated al-Ikhbariya TV.

Syrian state TV said two buses left early Monday and that 11 more buses were getting ready to move.

Syrian state media said dozens of civilians who had been held for years by the rebels were set free. The SANA news agency said the people were freed around midnight on Sunday, adding that they had been held by the Army of Islam group since 2013.

The evacuations follow a pattern of departures around the capital, Damascus, and other major Syrian cities as the government reasserts its control after seven years of war.

Human rights groups and U.N. officials say the tactic amounts to forced displacement, a war crime. The U.N. Security Council planned to hold an emergency meeting Monday to discuss the chemical attack.

In his tweets Sunday, Trump called Assad an "animal" and delivered a rare personal criticism of Russian President Vladimir Putin for supporting him. Trump has declared his intent to withdraw U.S. troops from Syria in the coming months, despite resistance from many of his advisers.

Syrian rescuers from the White Helmets documented 42 fatalities in Saturday's reported chemical attack but were impeded from searching further by strong odours that caused breathing difficulties, said Siraj Mahmoud, a spokesman for the group.

More than 500 people, mostly women and children, were brought to medical centres complaining of difficulties breathing, foaming at the mouth and burning sensations in the eyes. Some had bluish skin, a sign of oxygen deprivation, according to a statement, symptoms consistent with chemical exposure.

The Observatory gave a higher death toll, saying at least 80 people were killed in Douma, including around 40 who died from suffocation. But it said the suffocations were the result of shelters collapsing on people inside them.

In denying the chemical weapons allegations, a government statement said "the army, which is advancing rapidly and with determination, does not need to use any kind of chemical agents."

Russia denied any involvement in the attack. Maj. Gen. Yuri Yevtushenko was quoted by Russian news agencies Sunday as saying Russia was prepared to send specialists to Douma to "confirm the fabricated nature" of the reports.

In recent weeks, government forces have recaptured villages and towns in the eastern Ghouta suburbs of the capital. Douma was the only town left holding out.

A 2013 chemical attack in eastern Ghouta that killed hundreds of people was widely blamed on government forces. The U.S. threatened military action but later backed down.

Syria denies ever using chemical weapons during the war and says it eliminated its chemical arsenal under a 2013 agreement brokered by the U.S. and Russia.

Associated Press writers James Heintz and Nataliya Vasilyeva in Moscow, Albert Aji in Damascus, Syria, Tia Goldenberg in Jerusalem and Jonathan Lemire in Washington contributed to this report.

By Zeina Karam And Bassem Mroue, The Associated Press</s>President Donald Trump on Sunday warned of a "big price" after reports of a chemical weapons attack in Syria almost a year to the day since the US struck a Syrian air field.

"Many dead, including women and children, in mindless CHEMICAL attack in Syria," Trump tweeted. "Area of atrocity is in lockdown and encircled by Syrian Army, making it completely inaccessible to outside world. President Putin, Russia and Iran are responsible for backing Animal Assad. Big price..."

He continued, "....to pay. Open area immediately for medical help and verification. Another humanitarian disaster for no reason whatsoever. SICK!"

Syrian activist groups on Saturday said toxic gas inside barrel bombs dropped from helicopters over a rebel-held city in Syria killed dozens of civilians and wounded scores more. Syrian state news said an "official source" denied the allegations.</s>A missile attack on a Syrian military airport left several dead and wounded, state media said Monday, after the US warned Damascus and its allies over an earlier suspected chemical attack on a rebel-held town.

The strike on the Tayfur air base in the central province of Homs, came as international outrage mounts over an attack on Saturday in the rebel enclave of Eastern Ghouta.

"Several missiles hit the Tayfur airport. Our air defence systems are blocking the missile attack," state news agency SANA said early Monday.

It later added that there were "dead and wounded" in the strike, without giving exact casualty numbers.

The missile attack came shortly after US President Donald Trump issued a stark warning over an apparent "chemical" attack in Douma, the last rebel-controlled town in an eastern suburb of Damascus.

"Many dead, including women and children, in mindless CHEMICAL attack in Syria," Trump wrote on Twitter, lashing out at Syrian President Bashar al-Assad and Russia's Vladimir Putin, a key ally of the regime.

"President Putin, Russia and Iran are responsible for backing Animal Assad. Big price to pay," he said.

His comments came exactly a year and a day after the US fired cruise missiles at a Syrian air base in retaliation for a deadly sarin gas attack in 2017.

SANA first said the missile strike on the Tayfur base was a "suspected US attack," but later withdrew all reference to America. DM</s>President Trump on Sunday condemned a Saturday chemical attack in Syria and criticized Russian President Vladimir Putin and Iran for backing Syrian President Bashar al Assad, who Mr. Trump called an “animal.”

“Many dead, including women and children, in mindless CHEMICAL attack in Syria. Area of atrocity is in lockdown and encircled by Syrian Army, making it completely inaccessible to outside world,” the president tweeted.

“President Putin, Russia and Iran are responsible for backing Animal Assad. Big price…to pay. Open area immediately for medical help and verification. Another humanitarian disaster for no reason whatsoever. SICK!” Mr. Trump said.

Dozens of people were reportedly killed on Saturday in a chemical attack in Douma amid continued tensions between opposition activists and Syrian government forces. The Syrian government denied the allegations.

The attack in Douma comes almost exactly a year after a chemical attack in the northern Syrian town of Khan Sheikhoun killed dozens of people. That attack prompted the U.S. to launch several dozen Tomahawk cruise missiles at a Syrian air base.

On Sunday, Mr. Trump blamed President Obama for Mr. Assad’s continued hold on power in the region, saying Mr. Obama failed to enforce his own “red line” on the use of chemical weapons.

“If President Obama had crossed his stated Red Line In The Sand, the Syrian disaster would have ended long ago! Animal Assad would have been history!” Mr. Trump tweeted.

Sen. Lindsey Graham said Sunday that Mr. Trump is now confronted with a defining moment of his presidency, amid talk that he would like to de-escalate the U.S. military presence in the region.

“President Trump can reset the table here,” Mr. Graham said on ABC’s “This Week.” “If it becomes a tweet without meaning, then he’s hurt himself with North Korea. If he doesn’t follow through and live up to that tweet, he’s going to look weak in the eyes of Russia and Iran.”

“So this is [a] defining moment, Mr. President,” he said. “You need to follow through that tweet - show resolve that Obama never did to get this right.”

Douma is the last rebel stronghold in the suburbs of Damascus known as eastern Ghouta.

A chemical attack in eastern Ghouta in 2013 that was widely blamed on government forces killed hundreds of people, prompting the U.S. to threaten military action before later backing down.

Syrian opposition activists and rescuers said Sunday that the poison gas attack in Douma killed at least 40 people and that families were found suffocated in their homes and shelters, with foam on their mouths.

While the reports could not be independently verified, the opposition-linked Syrian Civil Defense were able to document 42 fatalities but were impeded from searching further by strong odors that gave their rescuers difficulties breathing, said Siraj Mahmoud, a spokesman for the group, which is known as the White Helmets.

A joint statement by the Civil Defense and the Syrian American Medical Society, a relief organization, said more than 500 people, mostly women and children, were brought to medical centers with difficulty breathing, foaming at the mouth, and burning of the eyes. It said patients gave off a chlorine-like smell. Some had blue skin, a sign of oxygen deprivation.

It said the symptoms were consistent with chemical exposure. One patient, a woman, had convulsions and pinpoint pupils, suggesting exposure to a nerve agent.

The Syrian Observatory for Human Rights said at least 80 people were killed in Douma on Saturday, including around 40 who died from suffocation. But it said the suffocations were the result of shelters collapsing on people inside.

The attacked occurred amid a resumed offensive by Syrian government forces after the collapse on Friday afternoon of a 10-day truce with the Army of Islam rebel group.

But in a statement posted on the state-run news agency SANA, the Syrian government strongly denied the allegations. It said the claims were “fabrications” by the Army of Islam, calling it a “failed attempt” to impede government advances.

Russia, the Syrian government most powerful ally — also denied any involvement in the alleged gas attack.

On Sunday, Maj. Gen. Yuri Yevtushenko was quoted by Russian news agencies as saying Russia was prepared to “promptly send Russian specialists in radiation, chemical and biological protection to Douma after its liberation from fighters to gather data that will confirm the fabricated nature of these statements.”

Mr. Yevtushenko said “a number of Western countries” are trying to prevent the resumption of an operation to remove Army of Islam fighters from Douma and “to this end they are using the West’s pet theme of the use of chemical weapons by Syrian forces.”

Syria denies ever using chemical weapons during the seven-year civil war, and says it eliminated its chemical arsenal under a 2013 agreement brokered by the U.S. and Russia after the attack in eastern Ghouta.
• This article is based in part on wire service reports.</s>The Britain-based Syrian Observatory for Human Rights said it was not clear who was behind Monday's early morning missile strike on the Syrian government's T4 air base.

It lies between Syria's third city Homs and the ancient town of Palmyra.

Most of those killed were either Iranians or members of Iran-backed groups, said Rami Abdurrahman, who heads the observatory, which has regularly monitored Syria's seven-year war.

Lebanese media said that residents living near that country's border with Syria had heard unidentified jets in the early morning hours of Monday.

Read more: Syria: rebels evacuate Douma under new agreement

Earlier, Syrian state media had spoken of dead and wounded at the base, without giving casualty figures.

The Pentagon said: "The Department of Defense is not conducting air strikes in Syria." Defense analysts quoted by Reuters said there were deployments of Russian forces at the base.

French armed forces spokesman Colonel Patrik Steiger also denied France carried out the strike, telling the French news agency AFP: "It was not us."

A military spokeswoman for Israel, which on occasions in the past has struck targets inside Syria, declined to comment on explosions at T4.

On Sunday French President Emmanuel Macron had spoken by phone with US President Donald Trump, who had previously warned there would be a "big price to pay" for Saturday's suspected poison-gas attack on Douma.

For weeks, the remnant rebel holdout east of Damascus has faced an offensive by Syrian government forces, prompting moves to evacuate civilians, although Jaish al-Islam rebels have not confirmed such a deal.

The Syrian government denied staging Saturday's suspected poison gas assault on Douma. Russia, Assad's ally, said such accounts were "fabricated."

Moscow said some 8,000 fighters and 40,000 civilians would be bussed out and said that proved "no chemical weapons were used in this area."

In February, Macron had said "France will strike" in the event of a lethal chemical weapon attack on civilians by government forces in Syria.

Relief workers inside Douma told AFP on Sunday that dead bodies still lay in the streets and hospitals were teeming with dead and wounded.

Douma was once one of the hubs of the 2011 Arab Spring uprising against Assad's government.

Read more: What does the chemical weapons watchdog OPCW do?

In April 2017, Trump ordered a strike on another Syrian air base, Shayrat, 70 kilometers (45 miles) west of T4, following similar allegations that Assad had used banned chemicals on civilians.

The UN Security Council has called an emergency meeting for Monday to discuss the incident amid worldwide outrage over the alleged used of poison gas.</s>BEIRUT: An alleged chemical attack in Syria's rebel-held Douma has sparked international outrage, with Washington warning on Sunday (Apr 8) of possible military action, while Damascus and Moscow said the reports were mere "fabrications".

Syria's White Helmets, who act as first responders in rebel-held areas of Syria, said the attack took place late on Saturday using "poisonous chlorine gas".

"More than 500 cases - the majority of whom are women and children - were brought to local medical centres with symptoms indicative of exposure to a chemical agent," according to a joint statement issued by the Syrian American Medical Society (SAMS) and the White Helmets.

Patients showed signs of "respiratory distress, central cyanosis, excessive oral foaming, corneal burns, and the emission of chlorine-like odour", it said.

The statement said civil defence volunteers had found 42 casualties dead in their homes "with similar clinical symptoms of excessive oral foaming, cyanosis, and corneal burns". Six others had died while receiving treatment.

Footage posted online by the White Helmets, which was not possible to verify, showed victims with yellowed skin crumpled on the ground and foaming at the mouth.

Douma is the last remaining opposition-held town in Eastern Ghouta, once the rebels' main bastion outside Damascus but now ravaged by a seven-week regime assault.

Since Feb 18, Syrian and Russian forces have waged a fierce military onslaught.

WHO WAS BEHIND IT?

While no one has yet provided evidence of its involvement, Syrian President Bashar al-Assad's regime has been repeatedly accused of using chemical weapons in the country's seven-year civil war.

The Syrian Observatory for Human Rights, a Britain-based monitor, said the regime carried out a wave of air strikes on Douma on Friday and Saturday that killed nearly 100 people, including many who suffered breathing difficulties.

Syria and its Russian ally denounced the claims as "fabrications", with Russia warning of potential "dire consequences" if they were used as a pretext for military action.

HOW HAS THE WORLD REACTED?

US President Donald Trump warned there would be a "big price to pay".

"Many dead, including women and children, in mindless CHEMICAL attack in Syria," Trump wrote on Twitter. "President (Vladimir) Putin, Russia and Iran are responsible for backing Animal Assad. Big price to pay."

United Nations chief Antonio Guterres said he was "particularly alarmed" by the attack, adding that if confirmed, the use of chemical weapons would be "abhorrent".

Britain called for an investigation into what it said were the "deeply disturbing" reports, and Turkey, which has backed rebels against Assad, said it had a "strong suspicion" the Syrian president was to blame.

France has repeatedly said that evidence of chemical weapons use in Syria could prompt military action and said Sunday it would "do its duty" following the latest allegations. It called for an emergency UN Security Council meeting.

Pope Francis described the allegations as "terrible news", saying: "Nothing, nothing can justify the use of such devices of extermination against defenceless people and populations."

WILL MILITARY ACTION BE TAKEN?

White House security adviser Tom Bossert refused to rule out US military action in response to the alleged chemical strike. "I wouldn't take anything off the table," he said.

US State Department spokeswoman Heather Nauert said the reports, if confirmed, "are horrifying and demand an immediate response by the international community."

Prominent Republican senator Lindsey Graham warned Trump that a failure to act now could leave him in a weakened posture internationally.

"It's a defining moment in his presidency," Graham said.

A chemical attack with the nerve agent sarin in the Eastern Ghouta enclave in August 2013 killed 1,429 people, including children, the US says.

Sarin was also detected in an April 2017 attack on the northwestern town of Khan Sheikhun that killed more than 80 people. The agent was released after an air strike.

Helicopter-dropped chlorine-filled munitions have been increasingly used by the regime as the conflict has dragged on, according to a 2017 report by Human Rights Watch.</s>WASHINGTON — President Donald Trump plans to confer with senior military leaders Monday, after he threatened a "big price to pay" for a suspected poison gas attack in Syria that killed women and children.

Trump was set to get a briefing and have dinner with military leaders. Monday is the first day on the job for his new national security adviser, John Bolton, who has previously advocated significant airstrikes against Syria.

The White House deliberations came as Russia and the Syrian military blamed Israel for a pre-dawn missile attack on a major air base in central Syria, saying Israeli fighter jets launched the missiles from Lebanon's air space. A war-monitoring group said the airstrikes killed 14 people, including Iranians active in Syria.

Syria's state news agency SANA initially said the attack on the T4 air base was likely "an American aggression," but Pentagon spokesman Christopher Sherwood quickly denied the United States was behind the strike and the agency then dropped the accusation, blaming Israel instead.

Saturday's suspected poison gas attack took place in a rebel-held town near Damascus amid a resumed offensive by Syrian government forces after the collapse of a truce. Syrian activists, rescuers and medics said the attack in Douma killed at least 40 people, with families found suffocated in their houses and shelters. The reports could not immediately be independently verified.

Officials in Washington worked Sunday to verify the claim by Syrian opposition activists and rescuers that the Assad government was responsible.

Just over a year ago, Trump ordered dozens of cruise missiles to be fired at a Syrian air base after declaring there was no doubt Assad had "choked out the lives of helpless" civilians in an attack that used banned gases. White House advisers said at the time that images of hurt children helped spur the president to launch that air strike, and television new shows on Sunday aired similar depictions of suffering young Syrians.

"Many dead, including women and children, in mindless CHEMICAL attack in Syria," Trump tweeted. "Area of atrocity is in lockdown and encircled by Syrian Army, making it completely inaccessible to outside world. President Putin, Russia and Iran are responsible for backing Animal Assad. Big price to pay. Open area immediately for medical help and verification. Another humanitarian disaster for no reason whatsoever. SICK!"

The developments come as Trump has moved to dramatically scale back U.S. goals in Syria, pushing for a quick military withdrawal despite resistance from many of his national security advisers. Trump has given no formal order to pull out the 2,000 U.S. troops in Syria or offered a public timetable other than to say the U.S. will withdraw as soon as the remaining Islamic State fighters can be vanquished.

But Trump has signalled to his advisers that, ideally, he wants all troops out within six months.</s>President Donald Trump on Sunday warned of a "big price" after reports of a chemical weapons attack in Syria almost a year to the day since the US struck a Syrian air field.

"Many dead, including women and children, in mindless CHEMICAL attack in Syria," Trump tweeted. "Area of atrocity is in lockdown and encircled by Syrian Army, making it completely inaccessible to outside world. President Putin, Russia and Iran are responsible for backing Animal Assad. Big price..."

He continued, "....to pay. Open area immediately for medical help and verification. Another humanitarian disaster for no reason whatsoever. SICK!"

Syrian activist groups on Saturday said toxic gas inside barrel bombs dropped from helicopters over a rebel-held city in Syria killed dozens of civilians and wounded scores more. Syrian state news said an "official source" denied the allegations.</s>WASHINGTON — President Donald Trump plans to confer with senior military leaders Monday, after he threatened a "big price to pay" for a suspected poison gas attack in Syria that killed women and children.

Trump was set to get a briefing and have dinner with military leaders. Monday is the first day on the job for his new national security adviser, John Bolton, who has previously advocated significant airstrikes against Syria.

The White House deliberations came as Russia and the Syrian military blamed Israel for a pre-dawn missile attack on a major air base in central Syria, saying Israeli fighter jets launched the missiles from Lebanon's air space. A war-monitoring group said the airstrikes killed 14 people, including Iranians active in Syria.

Syria's state news agency SANA initially said the attack on the T4 air base was likely "an American aggression," but Pentagon spokesman Christopher Sherwood quickly denied the United States was behind the strike and the agency then dropped the accusation, blaming Israel instead.

Saturday's suspected poison gas attack took place in a rebel-held town near Damascus amid a resumed offensive by Syrian government forces after the collapse of a truce. Syrian activists, rescuers and medics said the attack in Douma killed at least 40 people, with families found suffocated in their houses and shelters. The reports could not immediately be independently verified.

Officials in Washington worked Sunday to verify the claim by Syrian opposition activists and rescuers that the Assad government was responsible.

Just over a year ago, Trump ordered dozens of cruise missiles to be fired at a Syrian air base after declaring there was no doubt Assad had "choked out the lives of helpless" civilians in an attack that used banned gases. White House advisers said at the time that images of hurt children helped spur the president to launch that air strike, and television new shows on Sunday aired similar depictions of suffering young Syrians.

"Many dead, including women and children, in mindless CHEMICAL attack in Syria," Trump tweeted. "Area of atrocity is in lockdown and encircled by Syrian Army, making it completely inaccessible to outside world. President Putin, Russia and Iran are responsible for backing Animal Assad. Big price to pay. Open area immediately for medical help and verification. Another humanitarian disaster for no reason whatsoever. SICK!"

The developments come as Trump has moved to dramatically scale back U.S. goals in Syria, pushing for a quick military withdrawal despite resistance from many of his national security advisers. Trump has given no formal order to pull out the 2,000 U.S. troops in Syria or offered a public timetable other than to say the U.S. will withdraw as soon as the remaining Islamic State fighters can be vanquished.

But Trump has signaled to his advisers that, ideally, he wants all troops out within six months.

Republican Sen. John McCain of Arizona said Assad heard Trump's signal that he wanted to withdraw from Syria and, "emboldened by American inaction," launched the attack. In a statement, McCain said Trump "responded decisively" last year with the air strike and urged Trump to be forceful again to "demonstrate that Assad will pay a price for his war crimes."

Images released by the Syrian Civil Defense White Helmets, a volunteer organization, show children lying on the ground motionless and foaming at the mouth. The Assad government, in a statement posted on the state-run news agency SANA, denied responsibility.

Trump's homeland security adviser, Thomas Bossert, noted on ABC's "This Week" the timing of the suspected chemical attack — almost a year to the day of the U.S. missile strikes.

Asked about the potential for an American missile strike in response, Bossert said: "I wouldn't take anything off the table. These are horrible photos. We're looking into the attack at this point."

Trump's decision to single out Russian President Vladimir Putin in a tweet for supporting Assad appeared noteworthy because Trump long has been reluctant to personally criticize the Russian leader. Last month, Trump called Putin and, against the counsel of his advisers, congratulated the Russian president on his re-election and invited him to the White House.

Trump also invoked Iran in his series of tweets, further challenging Tehran while signaling he may scuttle its nuclear deal with the West. The president has often blamed his predecessor, Barack Obama, for Assad's continued grip on power after years of civil war.

Obama said in 2012 that Syria's use of chemical weapons would be a "red line" that would change his decision-making on intervening in the war and have "enormous consequences." After such an attack in 2013 killed hundreds outside Damascus, American ships in the Mediterranean were poised to launch missiles. But Obama pulled back after key U.S. ally Britain, as well as Congress, balked.

He opted for a Russian-backed proposal that was supposed to remove and eliminate Syria's chemical weapons stockpiles.
The death toll from yesterday's suspected chemical weapons attack in Douma, Syria, rises to at least 70, according to the White Helmets group. The Syrian government and Russia deny the allegations of a chemical attack.