United States naval vessels sailing through international waters in the South China Sea, including areas claimed by China or other nations, is not provocative and should surprise no one, the U.S. Navy's most senior uniformed officer said on Thursday.
China claims most of the South China Sea and has warned it will not stand for violations of its territorial waters in the name of freedom of navigation.
The United States says international law prohibits claiming territory around artificial islands built on previously submerged reefs.
"It should not come as a surprise to anybody that we will exercise freedom of navigation wherever international law allows," John Richardson, the U.S. chief of naval operations, told reporters in Tokyo.
"I don't see how this can be interpreted as provocative."
Some analysts in Washington believe the United States has already decided to conduct freedom-of-navigation operations inside 12 nautical mile limits that China claims around islands built on reefs in the Spratly archipelago in the South China Sea.
U.S. Defense Secretary Ash Carter delivers remarks at AUSA 2015 Annual Meeting and Exposition in Washington.
U.S. Secretary of Defense Ash Carter said on Tuesday the U.S. military would sail or fly wherever international law allowed.
Richardson, who was promoted to his post last month, is in Japan at the start of a 12-day trip around Asia and Europe. Starting in Japan, he said, showed the importance of the alliance between the two countries.