China, in an early test of US President Donald Trump, is nearly finished building almost two dozen structures on artificial islands in the South China Sea that appear designed to house long-range surface-to-air missiles, two US officials told Reuters.
The development is likely to raise questions about whether and how the United States will respond, given its vows to take a tough line on China in the South China Sea.
China claims almost all the South China Sea, which carries a third of the world's maritime traffic. Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have claims. Trump's administration has called China's island building in the South China Sea illegal.
Building the concrete structures with retractable roofs on Subi, Mischief and Fiery Cross reefs, part of the Spratly Islands chain where China already has built military-length airstrips, could be considered a military escalation, the US officials said in recent days, speaking on condition of anonymity.