“China respects and upholds the freedom of navigation and overflight in the South China Sea which countries enjoy under international law, but firmly opposes any country’s attempt to undermine China’s sovereignty and security in the name of the freedom of navigation and overflight,” the Chinese official said.
The United States has kept an eye on China's moves in the South China Sea but has not formally condoned or opposed them. The Navy has, however, conducted “freedom of navigation” operations to ensure safe passage. Those have been interpreted by China as shows of force, and have often warranted warnings from Beijing. Last year, a Chinese admiral said these moves could lead to “disaster.”
Senior members of the administration have taken hard lines against Chinese aggression in the South China Sea. In his confirmation hearing, Secretary of State Rex Tillerson said he’d tell China that “the island-building stops, and, second, your access to those islands is also not going to be allowed.” Though Defense Secretary James Mattis has said freedom of navigation is “absolute,” and that the Navy would “practice in international waters as appropriate,” he has said “at this time” there was no need for action.