China deployed surface-to-air missiles on a contested island in the South China Sea just prior to a Tuesday meeting between Asian leaders and President Barack Obama, according to media reports.
Satellite photos captured by ImageSat International on Feb. 14 show two batteries of missile systems and radar on China-controlled Woody Island, Fox News reported Wednesday.
An unidentified U.S. official confirmed the photos appeared to be a variant of the HQ-9 missile system, the report said.
Satellite photos taken Feb. 3 of Woody, the largest of the Paracel Islands, showed no missiles, Fox News reported.
Defense Department officials had not publicly commented on the photos by late Tuesday in Washington.
News of the missile deployment in the Paracels, which has been the scene of boat ramming and other confrontations between China and Vietnam, comes after Obama wrapped up a summit with Southeast Asian leaders Tuesday in California.
"Here at this summit, we can advance our shared vision of a regional order where international rules and norms, including freedom of navigation, are upheld and where disputes are resolved through peaceful, legal means," Obama said Monday.
Tensions in the East and South China seas over island disputes have mounted in recent years, leaving U.S. government officials concerned about the Navy's rights to freedom of navigation in an area where $1.2 trillion in U.S. trade transits annually.
Navy ships have sailed near rocks and artificial islands in the Spratly and Paracel chains to assert navigation rights generally accepted by most nations under the U.N. Convention on the Law of the Sea -- but not by China, which has condemned the U.S. operations.
China claims nearly 90 percent of the South China Sea and has claimed an Air Defense Identification Zone over parts of the East China Sea, including directly over the Japan-administered Senkaku Islands.
It has in recent years added about 3,000 acres of landfill to submerged reefs and built at least three runways capable of supporting military aircraft, according to 2015 Pentagon reports.
On Saturday, satellite images posted by China watcher Victor Robert Lee and Digital Globe showed new dredging about 15 miles from Woody Island, along with what appeared to be a helicopter base under construction in the Paracel chain.
China's continuing island-building, along with its use of coast guard and other non-military ships to enforce its claims, continues to concern Navy officials.
On Monday, 7th Fleet commander Vice Adm. Joseph Aucoin called on China to clear up the intent of its actions in the Western Pacific.
"I think that would relieve some of the angst that we are now seeing, that we are unsure where they are taking this," Aucoin told reporters in Singapore, according to Bloomberg News.
The Paracels are claimed by China, Vietnam and Taiwan.
In 1974, China invaded and occupied the western group of these islands, killing South Vietnamese forces there. After the fall of Saigon, communist Vietnam retained its claim to the islands.
In 2014, larger Chinese coast guard ships rammed Vietnamese fishing vessels in nearby waters, after China deployed a deepwater oil rig.