TOKYO — U.S.-Chinese tensions over the South China Sea will ratchet up another notch this weekend, when Secretary of State John Kerry plans to confront top officials in Beijing this weekend to protest China's growing territorial claims in the strategic waters.
The two nations already are playing a dangerous game of cat-and-mouse, as the U.S. military responds to a massive island-building campaign by China in one of the world's most crucial and hotly contested waterways.
Chinese warships this week closely shadowed a new, high-tech U.S. Navy warship during a patrol through a group of islands claimed all or in part by China and five other countries.
Although the encounters near the Spratly Islands were described by the commander of the USS Fort Worth as "professional," U.S. officials are concerned that China eventually could use the new islands as bases from which to restrict air and sea traffic in the region.
In a toughly worded statement this week, the State Department dismissed China's island-building as a territorial claim and said the U.S. government is determined to preserve freedom of navigation in the South China Sea and of the airspace above it, as is allowed under international conventions.
"International law is clear that land reclamation cannot change a submerged feature into an island that is entitled to maritime zones" controlled by a nation," the department said.
To back up the U.S. government's words, the Pentagon said it is considering tough new measures to ensure freedom of navigation and flight in the contested area, including sending military planes and ships within 12 miles of territory claimed by China, as a show of resolve.
In addition, Japan, which is shedding post-war restrictions on its military, this week sent two warships to conduct first-ever training exercises with the Philippine navy, also in the South China Sea.
The Chinese government issued its own warning. "The Chinese side will take resolute measures to safeguard national sovereignty and safety. We will keep an eye on the situation in relevant waters and airspace and respond to any violation of China's sovereignty and threat to China's national security," Hua Chunying, a spokeswoman for the Chinese Foreign Ministry, said Wednesday.
About $5 trillion in trade passes through shipping lanes in the South China Sea each year, according to the U.S. Navy. It is also a rich source of fish and other resources for neighboring countries.
The Fort Worth is one of the first of a new class of "littoral combat ships" designed to operate in shallow waters like the South China Sea and is part of a new U.S. focus on the Asia-Pacific region because of China's growing economic and military might. Eventually four of the ships will operate out of a "rotational" base in Singapore.
Although last week's patrol was described as "routine," the Fort Worth had not operated near the Spratly Islands since arriving in the region in December.
According to a Navy news release, the Fort Worth encountered "multiple" ships from China's People's Liberation Army-Navy during the week-long patrol, which ended May 13. Navy spokesman Lt. Cmdr. Clayton Doss said the patrol took place in international waters but he could not discuss precise locations.
Although the Navy released photos and video of at least one Chinese ship, the frigateYancheng, following the Fort Worth within close visual distance for at least two consecutive days, the American ship's commander said there were no untoward incidents.
He said ships on both sides had followed an international set of procedures known as CUES, or Code for Unplanned Encounters at Sea.
"Our interactions with Chinese ships continue to be professional and CUES helps clarify intentions and prevent miscommunication," Cmdr. Matt Kawas said.
Nonetheless, a more aggressive posture by U.S. forces could be risky, said Alessio Patalano, lecturer in war studies at the Department of War Studies at King's College London.
"The Chinese will not stand by. They're likely to deploy their own forces, both military and law enforcement. It's fair to assume it will get hotter around the area," said Patalano, who specializes in maritime security issues in Asia.
Last summer, a Chinese fighter jet performed an "unsafe" intercept of a Navy patrol plane operating in international airspace in the region, prompting a protest from Washington.
Tetsuo Kotani, a maritime security specialist at the Japan Institute of International Affairs, in Tokyo, said the U.S. likely is re-emphasizing a strategy known as the Freedom of Navigation Program, in which ships and planes are sent to challenge maritime claims deemed excessive.
"The FON Program will send a very strong message to China. I believe China will protest but at the same time China needs to respect U.S. determination. I expect Japan will assist the U.S. FON Program. The combined exercise with the Philippinesindicates Japan understands the need," Kotani said.
China claims sovereignty over virtually all of the South China Sea, including some islands more than 1,000 miles from its shores. Taiwan, the Philippines, Malaysia,Brunei and Vietnam have overlapping claims, as well.
Recent commercial satellite images show extensive landfill and construction on at least seven previously submerged reefs or atolls in the Spratly Islands group, including runways and port facilities that could accommodate military planes and ships.
"China is creating a 'Great Wall of Sand' with dredges and bulldozers," Adm. Harry Harris, commander of the U.S. Pacific Fleet, warned in a speech in Australia on April 1. Harris said that raises "serious questions about Chinese intentions."
Hua, the Chinese Foreign Ministry spokesperson, said last month that the new islands were intended for peaceful purposes, including maritime search and rescue, disaster prevention and mitigation, marine science and research. But Hua also acknowledged they would used to safeguard "territorial sovereignty and maritime rights and interests" and for "necessary military defense."
In congressional testimony earlier this week, David Shear, assistant secretary of defense for Asian and Pacific security affairs, said Chinese activity amounted to "a pattern of behavior that raises concerns that China is trying to assert de facto control over disputed territories, and strengthen its military presence in the South China Sea."