TOKYO: The United States' operating in international waters in the South China Sea should not come as a surprise and would not be a provocative act, the US Navy's most senior uniformed officer said on Thursday.

Chief of Naval Operations John Richardson, who was promoted to his post last month, made the remarks at a press roundtable in Tokyo at the start of a trip around Asia.

China claims most of the South China Sea and has warned that it would not stand for violations of its territorial waters in the name of freedom of navigation.

US Secretary of Defense Ash Carter said on Tuesday the US military would sail or fly wherever international law allowed.