Reuters reports that “the United States has seen Chinese activity around a reef China seized from the Philippines nearly four years ago that could be a precursor to more land reclamation in the disputed South China Sea, the U.S. Navy chief said on Thursday.”  

“The head of U.S. naval operations, Admiral John Richardson, expressed concern that an international court ruling expected in coming weeks on a case brought by the Philippines against China over its South China Sea claims could be a trigger for Beijing to declare an exclusion zone in the busy trade route.”  

“Richardson told Reuters the United States was weighing responses to such a move.”