Beijing warned Washington on Wednesday not to challenge its sovereignty in the South China Sea amid reports that the U.S. Navy was gearing up to sail more warships near China's man-made islands in the contested waters.

On Sunday, the Navy Times reported that U.S. naval leaders were hoping to ratchet up so-called freedom of navigation operations in the strategic waterway, citing unnamed officials. The report said that the operations could be carried out by warships with the San Diego-based Carl Vinson carrier strike group, which is currently sailing in the Western Pacific.

Chinese Foreign Ministry spokesman Geng Shuang, responding to a question about the report Wednesday, said Beijing has backed freedom of navigation in the waters, but opposes any U.S. actions that challenge its sovereignty and security.