By Christopher Bodeen, The Associated Press

BEIJING — China appears to have installed anti-aircraft and anti-missile weapons on its man-made islands in the strategically vital South China Sea, a U.S. security think tank says, upping the stakes in what many see as a potential Asian powder keg.

The Center for Strategic and International Studies, or CSIS, said in a report late Wednesday that the anti-aircraft guns and close-in weapons systems designed to guard against missile attack have been placed on all seven of China’s newly created islands.

White House spokesman Josh Earnest said Thursday that he could not confirm the report, but Republican Sen. John McCain, chairman of the Senate Armed Services Committee, said the imagery shows China is militarizing the South China Sea. He called for a “determined response” from the U.S. and its allies.

“The United States must take immediate steps to underscore our unwavering commitment to freedom of the seas and to enforce a stable balance of power in the region,” McCain said in a statement.

The outposts were built in recent years over objections by the U.S. and rival claimants by piling sand on top of coral reefs, followed by the construction of military-grade 3,000-meter (10,000-foot) airstrips, barracks, lighthouses, radar stations and other infrastructure.

CSIS based its conclusions on satellite images taken in mid-to-late November and published on the website of its Asia Maritime Transparency Initiative.

In a statement, China’s Defense Ministry repeated that development on the islands was mainly for civilian purposes, but added that defensive measures were “appropriate and legal.”

“For example, were someone to be threatening you with armed force outside your front door, would you not get ready even a slingshot?” the ministry statement said.

The Philippines, which has troops and villagers stationed on some reefs and islands near China’s new artificial islands, expressed concern despite recently improving relations with China.

“If true, it is a big concern for us and the international community who uses the South China Sea lanes for trade,” Defense Secretary Delfin Lorenzana said. “It would mean that the Chinese are militarizing the area, which is not good.”

CSIS experts wrote that China’s new island armaments “show that Beijing is serious about defense of its artificial islands in case of an armed contingency in the South China Sea.”

“Among other things, they would be the last line of defense against cruise missiles launched by the United States or others against these soon-to-be-operational air bases,” the report said.

Beijing says the islands are intended to boost maritime safety in the region while downplaying their military utility. They also mark China’s claim to ownership of practically the entire South China Sea.

Taiwan, Vietnam, the Philippines, Malaysia and Brunei also claim territory in the waterway through which an estimated $5 trillion in global trade passes each year, while the U.S. Navy insists on its right to operate throughout the area, including in waters close to China’s new outposts. China has strongly criticized such missions, known as freedom of navigation operations.

The U.S. has committed to beefing up its military presence in the area, although new uncertainty has been introduced by incoming president Donald Trump, who has called for a reconsideration of its commitments to its Asian allies, including Japan and South Korea, while simultaneously criticizing China and speaking with the president of China’s longtime rival Taiwan.

“The timing is significant in that these first clear images come amid Trump’s challenging comments about China and its South China Sea fortresses,” said Alexander Neill, a senior fellow for Asia-Pacific security for the International Institute for Strategic Studies based in Singapore.

Chinese President Xi Jinping said on a visit to the U.S. last year that “China does not intend to pursue militarization” of the area, prompting some foreign experts to accuse China of going back on its word with its new deployments.

Looking forward, the nature of China’s new military deployments will likely be calibrated in response to moves taken by the U.S., said the IISS’s Neill.

“China will argue that they are entitled to place whatever they want there in reaction to U.S. actions,” Neill said. “The big question is whether Trump will embark on a more strident or discordant policy in the South China Sea.”</s>Image copyright AMTI

New photographic evidence has emerged of "significant" Chinese military defences on artificial islands in the South China Sea, a think tank reports.

China had previously committed to not militarising its controversial developments in the region.

But satellite images published by a US group appear to show anti-aircraft guns and missile defence systems on the seven islands.

Several countries claim territorial rights in the South China Sea.

In a report on Wednesday, the Asia Maritime Transparency Initiative (AMTI) said it had been tracking construction of hexagon-shaped buildings on four of the Spratly islands for several months.

Image copyright AMTI

It said the new buildings were an "evolution" of structures on the three other islands, but it was now confident that all of the buildings housed military defences.

The group says that some buildings "host what are most likely anti-aircraft guns" which have visible gun barrels in satellite images, while others are probably what it terms close-in weapons systems (CIWS).

CIWS are defence platforms used to detect and shoot down missiles and other aircraft.

Some of the structures have been buried, the group said - which would make them less vulnerable to enemy strikes.

Image copyright AMTI

"These gun and probable CIWS emplacements show that Beijing is serious about defence of its artificial islands in case of an armed contingency in the South China Sea," AMTI said.

"Among other things, they would be the last line of defence against cruise missiles launched by the United States or others against these soon-to-be-operational air bases," it added, in a reference to previous photos which seemed to show aircraft hangars being built.

China's Defence Ministry said on Thursday that its deployment of military equipment was "legitimate and lawful". A brief post on the Defence Ministry's microblog site described the equipment as necessary and defensive.

During his state visit to the US in September 2015, Chinese leader Xi Jinping said China did not intend to pursue militarisation of the Spratly islands but emphasised China's sovereignty over the region.

Image copyright Reuters Image caption The USS Decatur sailed near the disputed Paracel Islands

The contested region holds crucial shipping lanes - which prompted the United States to send a warship into the area in October.

The White House said it was to "demonstrate ... lawful uses of the sea that the United States and all states are entitled to exercise under international law."

China accused the US of an illegal act, and of being "intentionally provocative".

China claims almost all of the South China Sea, including reefs and islands also claimed by other nations, and has caused dismay in the region by building artificial islands and restricting access.

But Vietnam, the Philippines, Taiwan, Malaysia and Brunei all have competing claims.

In July, an international tribunal ruled against Chinese claims to rights in the South China Sea, backing a case brought by the Philippines.

China, however, called the ruling "ill-founded" and says it will not be bound by it.</s>Beijing: China's military has carried out its first ever live-fire drills using an aircraft carrier and fighters in the northeastern Bohai Sea close to Korea, state media said.

China's growing military presence in the disputed South China Sea has fuelled concern, with the United States criticising its militarization of maritime outposts and holding regular air and naval patrols to ensure freedom of navigation.

No other country has claims in China's busy waterway of the Bohai Sea, but the drills come amid new tension over self-ruled Taiwan, following US President-elect Donald Trump's recent telephone call with the island's president that upset Beijing.

Ten vessels and 10 aircraft engaged in air-to-air, air-to-sea and sea-to-air combat drills that featured guided missiles, state broadcaster Chinese Central Television reported late on Thursday.

"This is the first time an aircraft carrier squadron has performed drills with live ammunition and real troops," it said.

China's Soviet-built Liaoning aircraft carrier and a formation of warships carried out aerial interception, anti-aircraft and anti-missile drills, in which Shenyang J-15 fighter jets carrying live missiles also participated, CCTV said.

It broadcast images of fighter jets taking off from the carrier, firing missiles and destroying a target at sea.

The Liaoning has participated in previous military exercises, including some in the South China Sea, but the country is still years off from perfecting carrier operations similar to those the United States has practiced for decades.

On Wednesday, a US think tank said China had been installing anti-aircraft and anti-missile systems on artificial islands in the South China Sea, prompting China to defend its right to install military hardware there.

China's exercises aim to test the equipment and troop training levels, an unidentified navy official told the official China News Service.

Last December the Defence Ministry confirmed China was building a second aircraft carrier to go with the existing vessel, but its launch date is unclear.

China keeps its aircraft carrier programme a state secret, and CCTV blurred images showing the cockpit instrument panel of one aircraft involved in the Bohai Sea drills.

Beijing could build multiple aircraft carriers over the next 15 years, the Pentagon said in a report last year.

China's successful operation of the Liaoning is the first step in what state media and some military experts believe will be the deployment of domestically built carriers by 2020.</s>China’s Defense Ministry did not specify what kinds of weapons the new satellite images showed but said any military hardware on the islands was reasonable.

BEIJING — China signaled Thursday that it had installed weapons on disputed South China Sea islands and would use them like a “slingshot” to repel threats, compounding tensions with the incoming Trump administration.

The Chinese message, in a Defense Ministry statement, suggested China was further watering down a pledge made by its president, Xi Jinping, to not militarize the islands.

The comments left little doubt that such installations were part of China’s plan to deepen its territorial claim over the islands, which has raised tensions with its neighbors and the United States over freedom of navigation in the South China Sea, one of the world’s busiest commercial waterways.

They also were likely to further complicate China’s testy relations with President-elect Donald Trump. China’s rapid creation of artificial islands in the South China Sea, expanding former reefs and outcrops into guarded permanent outposts, already has become a major source of tension with the U.S. government.

The United States has said it will defend freedom of navigation in the South China Sea. The Chinese have accused the United States in recent weeks of “provocative” moves by sending warships near some of these islands, known as the Spratlys.

The Chinese have been creating harbors, runways and reinforced hangars big enough for military aircraft on the islands. But new satellite images made public this week appeared to reveal weapons placements for the first time.

The Center for Strategic and International Studies in Washington released the images through its Asia Maritime Transparency Initiative and said they showed “large anti-aircraft guns and probable close-in weapons systems,” which can theoretically thwart cruise-missile attacks.

China’s Defense Ministry statement, posted on its website in response to the images, did not specify what kinds of weapons they showed but said any military hardware on the islands was reasonable. It repeated China’s contention that its construction on the islands is mainly for civilian purposes.

“As for necessary military facilities, they are primarily for defense and self-protection, and this is proper and legitimate,” the Defense Ministry said. “For instance, if someone was at the door of your home, cocky and swaggering, how could it be that you wouldn’t prepare a slingshot?”

There was no immediate comment from Trump or his transition team.

Trump recently angered Chinese officials by holding a phone conversation with Tsai Ing-wen, the president of Taiwan, an island that China deems a breakaway province. It had been nearly four decades since a U.S. president or president-elect had such direct contact with a Taiwanese leader.

In an interview broadcast Sunday, Trump also criticized China over its trade imbalance with the United States, its military activities in the South China Sea and its ties to North Korea. China was “building a massive fortress in the middle of the South China Sea, which they shouldn’t be doing,” he said on Fox News.

During his campaign, Trump dwelled on accusations that China had systematically sapped U.S. industrial might, and he has indicated that trade issues will be a priority in dealings with Beijing. But the latest disclosures suggest how remote islands in the South China Sea could become a source of serious tensions, even military strife.

The Spratlys, which China calls the Nansha Islands, are the subject of an especially volatile mix of competing claims. Parts of the archipelago are also claimed by the Philippines, Malaysia, Vietnam, Brunei and Taiwan. And the possibility of undersea oil and gas deposits has exacerbated the rivalries.

China, with the world’s second-biggest economy and a swelling military budget, has established an intimidating dominance across much of the South China Sea. The latest satellite images appeared to confirm its deepening military grip on the Spratlys.

The steps “show that Beijing is serious about defense of its artificial islands in case of an armed contingency in the South China Sea,” the Asia Maritime Defense Initiative said in its report about the images.

“Among other things, they would be the last line of defense against cruise missiles launched by the United States or others against” air bases that may soon go into operation on the islands, it said.

The images showed that the facilities were in place before Trump’s comments.

The Obama administration sought to play down both the images and the Chinese Defense Ministry’s response. “We watch Chinese naval developments very carefully, and we urge all parties in the South China Sea to avoid actions that raise tensions,” said Capt. Jeff Davis, a Pentagon spokesman.

The images elicited a far more contentious response from hawkish Republicans, who do not necessarily share Trump’s views on China trade policy but see China’s actions in the South China Sea as an aggressive challenge to the United States.

Sen. John McCain, chairman of the Senate Armed Services Committee, said the images confirmed “what has long been evident: China is militarizing the South China Sea, its leaders continue to lie about that fact, and Beijing is paying little to no price for its behavior.”

The Chinese government has said it respects freedom of civilian passage in the South China Sea but also called U.S. naval “freedom of navigation operations” dangerous meddling. The Chinese navy has not tried to block the operations.

Previous satellite pictures of the islands, released by the Asia Maritime Defense Initiative in August, show that China was building military facilities there. Those images appeared to show reinforced aircraft hangars at the Fiery Cross, Subi and Mischief Reefs, all part of the disputed parts of the archipelago.

A spokesman for China’s Ministry of Foreign Affairs said Thursday that his government had been entitled to take such steps and said they did not count as “militarization.”</s>China's growing military presence in the disputed South China Sea has fueled concern, with the United States criticizing its militarization of maritime outposts and holding regular air and naval patrols to ensure freedom of navigation.

No other country has claims in China's busy waterway of the Bohai Sea, but the drills come amid new tension over self-ruled Taiwan, following U.S. President-elect Donald Trump's recent telephone call with the island's president that upset Beijing.

Ten vessels and 10 aircraft engaged in air-to-air, air-to-sea and sea-to-air combat drills that featured guided missiles, state broadcaster Chinese Central Television reported late on Thursday.

"This is the first time an aircraft carrier squadron has performed drills with live ammunition and real troops," it said.

China's Soviet-built Liaoning aircraft carrier and a formation of warships carried out aerial interception, anti-aircraft and anti-missile drills, in which Shenyang J-15 fighter jets carrying live missiles also participated, CCTV said.

It broadcast images of fighter jets taking off from the carrier, firing missiles and destroying a target at sea.

The Liaoning has participated in previous military exercises, including some in the South China Sea, but the country is still years off from perfecting carrier operations similar to those the United States has practiced for decades.

On Wednesday, a U.S. think tank said China had been installing anti-aircraft and anti-missile systems on artificial islands in the South China Sea, prompting China to defend its right to install military hardware there.

China's exercises aim to test the equipment and troop training levels, an unidentified navy official told the official China News Service.

Last December the Defence Ministry confirmed China was building a second aircraft carrier to go with the existing vessel, but its launch date is unclear.

China keeps its aircraft carrier program a state secret, and CCTV blurred images showing the cockpit instrument panel of one aircraft involved in the Bohai Sea drills.

Beijing could build multiple aircraft carriers over the next 15 years, the Pentagon said in a report last year.

China's successful operation of the Liaoning is the first step in what state media and some military experts believe will be the deployment of domestically built carriers by 2020.</s>The Asia Maritime Transparency Initiative (AMTI) at the Center for Strategic and International Studies said its findings, made available first to Reuters on Wednesday, were based on analysis of satellite images of islands in the strategic trade route, where territory is claimed by several countries.

The United States has previously criticized what it called China's militarization of its maritime outposts, and stressed the need for freedom of navigation by conducting periodic air and naval patrols near them that have angered Beijing.

China's Defence Ministry said in a statement on its website on Thursday that the construction it had carried out on islands and reefs in the disputed Spratlys chain was "mainly for civilian use".

"As for necessary military installations, they are mainly for defence and self-protection and are legitimate and lawful," it said. "If someone makes a show of force at your front door, would you not ready your slingshot?"

The United States has conducted four freedom of navigation patrols, seen as a challenge to China's extensive territorial claims in the South China Sea, in the past year or so, most recently in October.

AMTI said satellite images of islands China has built in the Spratlys showed what appeared to be anti-aircraft guns and what were likely to be close-in weapons systems (CIWS) to protect against cruise missile strikes.

Other images showed towers that likely contained targeting radar, it said.

Beijing regards the islands as its sovereign territory, and has often said it is entitled to limited and necessary defensive installations.

AMTI director Greg Poling said the think-tank had spent months trying to figure out the purposes of the structures shown in the images.

"This is the first time that we're confident in saying they are anti-aircraft and CIWS emplacements. We did not know that they had systems this big and this advanced there," he told Reuters.

"This is militarization. The Chinese can argue that it's only for defensive purposes, but if you are building giant anti-aircraft gun and CIWS emplacements, it means that you are prepping for a future conflict."

Chinese Foreign Ministry spokesman Geng Shuang told a regular news briefing in Beijing that he "did not understand" the situation referred to in the AMTI report.

"The Nansha islands are China's inherent territory. China's building of facilities and necessary territorial defensive facilities on its own territory is completely normal," he said, using China's name for the Spratlys.

"If China's building of normal facilities and deploying necessary territorial defensive facilities on its own islands is considered militarization, then what is the sailing of fleets into the South China Sea?"

The Philippines, one of several countries with competing territorial claims in the South China Sea, said it was still verifying the report.

"But if true it is a big concern for us and the international community who use the South China Sea lanes for trade," said Defence Minister Delfin Lorenzana. "It would mean that the Chinese are militarising the area which is not good."

Lorenzana's comments were made during a visit to Singapore with President Rodrigo Duterte, where he also said the United States had agreed to sell the Philippine Navy two advanced radar systems to boost its surveillance capability in the South China Sea.

Australia too voiced concerns about China's actions in the disputed waterway.

"The building of artificial islands and the possible militarization is creating an environment of tension and mistrust between claimants and other regional states," said Foreign Minister Julie Bishop in a statement.

"We urge claimants to refrain from coercive behavior and unilateral actions designed to change the status quo in disputed areas."

U.S. President-elect Donald Trump, who takes office on Jan. 20, has criticized Chinese behavior in the South China Sea, while signaling he may adopt a tougher approach to China's assertive behavior in the region than President Barack Obama.

The State Department said it would not comment on intelligence matters, but spokesman John Kirby added: "We consistently call on China as well as other claimants to commit to peacefully managing and resolving disputes, to refrain from further land reclamation and construction of new facilities and the militarization of disputed features."</s>MANILA: The Chinese and Philippine coast guards met for the first time on Friday and agreed to move forward on maritime cooperation, officials said, as relations between Beijing and Manila warm under Philippine President Rodrigo Duterte.

The two-day meeting in Manila on establishing a Joint Coast Guard Committee (JCGC) came just days after new images showed China had apparently installed defensive weapons on artificial islands in the hotly contested South China Sea.

In a joint statement, the coast guards said possible areas for cooperation included fighting drug trafficking and other maritime crimes, environmental protection and search and rescue.

“This is a milestone because it opened the communication lines between the two agencies involved in the (South China Sea),” Philippine coast guard spokesman Armand Balilo told Agence France-Presse.

China claims most of the strategic South China Sea—despite partial counter-claims by the Philippines, Brunei, Malaysia, Taiwan and Vietnam—and Chinese coast guard vessels have become an ever-growing presence in the waterway.

Balilo said territorial issues were not discussed, but the meeting was a “confidence-building measure” resulting from Duterte’s trip to China in October.

Duterte, 71, has pivoted his nation’s foreign policy away from traditional ally the United States towards China and Russia.

His predecessor, Benigno Aquino 3rd, had angered China by asking a UN-backed tribunal to outlaw Beijing’s claims to most of the South China Sea.

A July ruling gave Manila a sweeping victory but Duterte vowed not to “taunt or flaunt” it as he sought to improve economic relations, while praising China’s support for his deadly drug war.

Philippine ambassador to China Jose Santiago Santa Romana said “sensitive” issues would be tackled separately.

“It will be discussed using quiet diplomacy as well as high-level diplomacy,” Santa Romana told ABS-CBN television.

The meeting took place after a US think tank released images Wednesday that appeared to show China had installed “significant” defensive weapons on artificial islands it had controversially built over contested reefs.

Philippine Defense Minister Delfin Lorenzana said Manila was trying to verify the report but if true, it was a “big concern” for the international community as it would mean China was “militarizing” the area.

The Philippines will host the inaugural meeting of the JCGC in February. AFP</s>China appears to have installed anti-aircraft and anti-missile weapons on its man-made islands in the ­strategically vital South China Sea, a US security think-tank has said.

The Centre for Strategic and International Studies (CSIS) said in a report that the anti-aircraft guns and close-in weapons systems designed to guard against missile attack have been placed on all seven of China’s newly created islands.

The outposts were built in recent years over objections by the US and rival claimants by piling sand on top of coral reefs, followed by the construction of military grade 10,000ft airstrips, barracks, lighthouses, radar stations and other infrastructure.

CSIS based its conclusions on satellite images taken in mid-to-late November and published on the website of its Asia Maritime Transparency Initiative.

China’s defence ministry repeated that development on the islands was mainly for civilian purposes, but added that defensive measures were “appropriate and legal”.

“For example, were someone to be threatening you with armed force outside your front door, would you not get ready even a slingshot?” the ministry statement said.

The Philippines, which has troops and villagers stationed on some reefs and islands near China’s new artificial islands, expressed concern despite recently improving relations with China.

“If true, it is a big concern for us and the international community who uses the South China Sea lanes for trade,” defence secretary Delfin Lorenzana said.

“It would mean that the Chinese are militarising the area, which is not good.”

China’s new island armaments “show that Beijing is serious about defence of its artificial islands in case of an armed contingency in the South China Sea,” CSIS experts wrote in the report.

“Among other things, they would be the last line of defence against cruise missiles launched by the US or others against these soon-to-be-operational air bases,” the report said.

Beijing said the islands are intended to boost maritime safety in the region while downplaying their military utility. They also mark China’s claim to ownership of practically the entire South China Sea.

Taiwan, Vietnam, the Philippines, Malaysia and Brunei also claim territory in the waterway through which an estimated $5 trillion in global trade passes each year, while the US Navy insists on its right to operate throughout the area, including in waters close to China’s new outposts.</s>BEIJING—A US think tank says recent satellite images appear to show that China has installed anti-aircraft and antimissile weapons on its man-made islands in the strategically vital South China Sea, upping the stakes in what many see as a potential Asian powder keg.

The Center for Strategic and International Studies (SIS) said in a report late Wednesday the anti-aircraft guns and close-in weapons systems designed to guard against missile attack have been placed on all seven of China’s newly created islands.

The outposts were built in recent years by piling sand on top of coral reefs,

 followed by the construction of military-grade 3,000-meter (10,000-foot) airstrips, barracks, lighthouses radar stations and other infrastructure.

CSIS based its conclusions on satellite images taken of the islands in mid- to late-November, and published on the web site of its Asia Maritime Transparency Initiative.

China’s new island armaments “show that Beijing is serious about defense of its artificial islands in case of an armed contingency in the South China Sea,” CSIS experts wrote in the report.

“Among other things, they would be the last line of defense against cruise missiles launched by the United States or others against these soon-to-be-operational air bases,” the report said.

China’s defense ministry did not immediately respond on Thursday to a faxed request for comment. Beijing says the manufactured islands are intended to boost maritime safety in the region while downplaying their military utility.

They also mark China’s claim to ownership of practically the entire South China Sea, its islands, reefs and other maritime features.

Taiwan, Vietnam, the Philippines, Malaysia and Brunei Darussalam also claim territory in the waterway through which an estimated $5 trillion in global trade passes each year, while the US Navy insists on its right to operate throughout the area, including in waters close to China’s new outposts. China has strongly criticized such missions, formally termed Freedom of Navigation Operations.

The US has committed to beefing up its military presence in the area, although new uncertainty has been introduced by incoming President Donald J. Trump who broke long-established diplomatic protocol by talking on the phone earlier this month with the president of China’s longtime rival Taiwan.

Trump has called for a reconsideration of its commitments to its Asian allies, including Japan and South Korea, while simultaneously criticizing Chinese trade policy toward the US, along with its new territorial assertiveness.

Trump referred to China’s man-made islands in a tweet earlier this month, saying Beijing didn’t ask the US if it was OK to “build a massive military complex in the South China Sea.”

“The timing is significant in that these first clear images come amid Trump’s challenging comments about China and its South China Sea fortresses,” said Alexander Neill, a senior fellow for Asia-Pacific security for the International Institute for Strategic Studies based in Singapore.

In all, China has reclaimed more than 1,295 hectares (3,200 acres) of land in the southeastern South China Sea. The US says the building doesn’t give China any additional territorial rights and an international arbitration panel in The Hague ruled over the summer against China’s historical claim to ownership of waters within the South China Sea. Beijing has ignored the ruling.

China has sought to emphasize the usefulness of the island developments for civilian navigation in the area, while also asserting its right to equip them with whatever means deemed necessary for their defense. Chinese President Xi Jinping said on a visit to the US last year that “China does not intend to pursue militarization” of the area, prompting some foreign experts to accuse China of going back on its word with its new deployments.

Despite that, China considers it vital to equip the islands with defensive means given their distance—1,600 kilometers (1,000 miles)—from the Chinese mainland, together with the nearby presence of forces from rival claimants, such as Vietnam, said Yue Gang, a retired colonel and military analyst.

“As the matter of fact, these occupied islands have been armed and fortified for a long time,” Yue said. “No country in the world would only commit to providing civil services without considering its own security safety.”</s>The Asia Maritime Transparency Initiative (AMTI) at the Center for Strategic and International Studies said its findings, made available first to Reuters on Wednesday, were based on analysis of satellite images of islands in the strategic trade route, where territory is claimed by several countries.

The United States has previously criticized what it called China's militarization of its maritime outposts, and stressed the need for freedom of navigation by conducting periodic air and naval patrols near them that have angered Beijing.

China's Defence Ministry said in a statement on its website on Thursday that the construction it had carried out on islands and reefs in the disputed Spratlys chain was "mainly for civilian use".

"As for necessary military installations, they are mainly for defence and self-protection and are legitimate and lawful," it said. "If someone makes a show of force at your front door, would you not ready your slingshot?"

The United States has conducted four freedom of navigation patrols, seen as a challenge to China's extensive territorial claims in the South China Sea, in the past year or so, most recently in October.

AMTI said satellite images of islands China has built in the Spratlys showed what appeared to be anti-aircraft guns and what were likely to be close-in weapons systems (CIWS) to protect against cruise missile strikes.

Other images showed towers that likely contained targeting radar, it said.

Beijing regards the islands as its sovereign territory, and has often said it is entitled to limited and necessary defensive installations.

AMTI director Greg Poling said the think-tank had spent months trying to figure out the purposes of the structures shown in the images.

"This is the first time that we're confident in saying they are anti-aircraft and CIWS emplacements. We did not know that they had systems this big and this advanced there," he told Reuters.

"This is militarization. The Chinese can argue that it's only for defensive purposes, but if you are building giant anti-aircraft gun and CIWS emplacements, it means that you are prepping for a future conflict."

Chinese Foreign Ministry spokesman Geng Shuang told a regular news briefing in Beijing that he "did not understand" the situation referred to in the AMTI report.

"The Nansha islands are China's inherent territory. China's building of facilities and necessary territorial defensive facilities on its own territory is completely normal," he said, using China's name for the Spratlys.

"If China's building of normal facilities and deploying necessary territorial defensive facilities on its own islands is considered militarization, then what is the sailing of fleets into the South China Sea?"

The Philippines, one of several countries with competing territorial claims in the South China Sea, said it was still verifying the report.

"But if true it is a big concern for us and the international community who use the South China Sea lanes for trade," said Defence Minister Delfin Lorenzana. "It would mean that the Chinese are militarising the area which is not good."

Lorenzana's comments were made during a visit to Singapore with President Rodrigo Duterte, where he also said the United States had agreed to sell the Philippine Navy two advanced radar systems to boost its surveillance capability in the South China Sea.

Australia too voiced concerns about China's actions in the disputed waterway.

"The building of artificial islands and the possible militarization is creating an environment of tension and mistrust between claimants and other regional states," said Foreign Minister Julie Bishop in a statement.

"We urge claimants to refrain from coercive behavior and unilateral actions designed to change the status quo in disputed areas."

U.S. President-elect Donald Trump, who takes office on Jan. 20, has criticized Chinese behavior in the South China Sea, while signaling he may adopt a tougher approach to China's assertive behavior in the region than President Barack Obama.

The State Department said it would not comment on intelligence matters, but spokesman John Kirby added: "We consistently call on China as well as other claimants to commit to peacefully managing and resolving disputes, to refrain from further land reclamation and construction of new facilities and the militarization of disputed features."
Satellite images show anti-aircraft guns and missile defence systems being built on artificial islands in the South China Sea; China had previously committed to not militarising its controversial developments in the region.