U.S. naval vessels sailing through international waters in the South China Sea, including areas claimed by China, cannot be considered provocative, the U.S. Navy's most senior uniformed officer said on Thursday, while a Chinese newspaper called for a firm response to any "unscrupulous" U.S. behavior.
China has overlapping claims with Vietnam, the Philippines, Malaysia, Taiwan and Brunei in the South China Sea, through which $5 trillion in ship-borne trade passes every year.
Beijing 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."
Chinese Foreign Ministry spokeswoman Hua Chunying repeated that China has consistently respected and safeguarded freedom of navigation and overflight in the South China Sea.
"But we resolutely oppose any country doing harm to another country's sovereignty and security in the name of freedom of navigation and overflight," she told reporters.
The Global Times, a widely read and influential tabloid, said in an editorial that these potential U.S. patrols were not really about freedom of navigation, but a show of strength intended to emphasize U.S. global hegemony.
"From this perspective, China absolutely must not permit the U.S. side's warships and planes to behave unscrupulously near islands and reefs reclaimed by China and in skies overhead, and challenge China's bottom line," said the paper, which is published by the ruling Communist Party's official People's Daily
"China's naval and air capacities must prepare, watch for U.S. military provocations and respond accordingly with countermeasures," it added.
"If the U.S. side openly and repeatedly enters the 12-nautical mile zone and its airspace, then there needs to be a firm counterattack."
Some analysts in Washington believe the United States has already decided to conduct freedom-of-navigation operations inside the 12-nautical-mile limits that China claims around islands built on reefs in the Spratly archipelago.
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.