Exclusive - China finishing South China Sea buildings that could house missiles: U.S. officials

A satellite image shows what CSIS Asia Maritime Transparency Initiative says appears to be anti-aircraft guns and what are likely to be close-in weapons systems (CIWS) on the artificial island Fiery Cross Reef in the South China Sea in this image released on December 13, 2016. CSIS Asia Maritime Transparency Initiative/DigitalGlobe/Handout via REUTERS

WASHINGTON (Reuters) - China, in an early test of U.S. President Donald Trump, has 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 U.S. 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.