US officials accuse China of intending to deploy long-range surface-to-air missiles on its artificial islands in the disputed South China Sea.
China has almost completed the construction of concrete storage structures on Subi, Mischief and Fiery Cross reefs, which are part of the Spratly Islands chain, Reuters reported Wednesday, citing unnamed US officials.
Featuring retractable roofs, the buildings appear to be 20 meters (66 feet) long and 10 meters (33 feet) high, an official said.
“It is not like the Chinese to build anything in the South China Sea just to build it, and these structures resemble others that house SAM batteries, so the logical conclusion is that's what they are for,” said another US official.
The officials said that Washington might view the move as a military escalation in the region, but an equal military response was out of question.
"The logical response would also be political – something that should not lead to military escalation in a vital strategic area," he said.
The US has for long accused China of undertaking a land reclamation program in the South China Sea for military purposes.
The new US administration has sent warships to challenge China’s sovereignty claims over most of the waters, which serve as a gateway for around a third of the world’s annual maritime trade.
The Philippines, one of the several countries that have overlapping claims with China, said Tuesday that any weapons deployment to the Chinese islands was “very unsettling” for the Southeast Asian countries.
A Pentagon spokesman told Reuters that Washington remained committed to “non-militarization in the South China Sea,” echoing President Donald Trump’s stance on the issue.
Trump has repeatedly attacked China’s growing influence in the region, pledging to prevent Beijing from building what he calls a “massive military complex” in the sea.
Despite the unofficial claims, US Secretary Rex Tillerson tried to de-escalate the tensions between the two countries in a phone conversation with Yang Jiechi, China's state councilor who outranks the foreign minister.
"Secretary Tillerson and State Councilor Yang affirmed the importance of a constructive bilateral relationship," the State Department said Tuesday.
Speaking to Chinese media, Yang said he hoped the two sides could “uphold the principles of non-conflict, non-confrontation, mutual respect and win-win cooperation.”
During his Senate confirmation hearings, Tillerson had stated that China should stop its island-building activities in the South China Sea and lose access to the ones it has already built.