Vietnam and China have concluded two days of joint naval patrols, including a port call in China, despite a heated dispute over claims in the South China Sea, state media said Tuesday.
Two boats from each country participated in the patrols Sunday and Monday, sailing more than 300 nautical miles in the Gulf of Tonkin bordering Vietnam and China, Vietnam's People's Army Newspaper said. A demarcation treaty for the area was signed in 2000.
"Respecting the signed agreements is one of the factors that will promote the friendly and neighborly relations between two countries and ensure sustainable stability and security at sea," it quoted Col. Nguyen Van Kiem, deputy chief of staff of Vietnam's navy, as saying.
Chinese Foreign Ministry spokesman Hong Lei did not comment on the joint patrol at a regular news conference Tuesday. He reiterated Beijing's sovereignty over the South China Sea, but said it would work toward a peaceful resolution to the territorial dispute.
The joint patrol was the 11th since 2005 between the neighboring Communist countries, but it was unclear how long it had been planned or whether it signaled any cooling of tempers. Relations between the two have plummeted in recent weeks as they have traded diplomatic punches over run-ins involving territory in the South China Sea claimed by both.
"The South China Sea has led to a souring of political relations but has not yet spilled over to affect the broad and deep nature of Sino-Vietnam relations," Carlyle Thayer, a Vietnam expert at the Australian Defense Force Academy in Canberra, said in an email. "The holding of the exercises is a good sign."
Last week, Vietnam held live-fire naval drills off its central coast and issued an order outlining who would be exempt from a military draft during wartime. China announced a few days later that it also recently held similar maneuvers in the South China Sea without providing exact dates.
On Tuesday, a newspaper published by China's ruling Communist Party ran a scathing editorial, warning Vietnam to back off.
"If Vietnam wishes to create a war in the South China Sea, China will resolutely keep them company," the Global Times said. "China has the absolute might to crush the naval fleets sent from Vietnam. China will show no mercy to its rival due to 'global impact' concerns."
China has been upset with Vietnam's welcoming of U.S. involvement in helping resolve disputes in the South China Sea that Beijing believes should be settled bilaterally. The editorial said any attack on Vietnam would likely not lead to a direct conflict with the U.S., but that "even if some friction occurs, that is no reason for China to put up with Vietnam's unlimited vice in the South China Sea."
The U.S. has said that keeping key shipping lanes open in the South China Sea is in its national interest.
On Monday, U.S. Republican Sen. John McCain, a former prisoner of war in Vietnam, told a conference held by the Center for Strategic and International Studies, a Washington think tank, that Chinese aggressive behavior and unsubstantiated territorial claims are "exacerbating tensions in the South China Sea."
He urged the U.S. to help Southeast Asian nations resolve territorial disputes with China, while also assisting them in developing and deploying maritime defense systems, including early warning radar and coastal security vessels.
Hundreds of Vietnamese protested Sunday for the third straight week, yelling "Down with China!" as they marched through the streets of the capital, Hanoi. Many also carried signs demanding that China stop entering Vietnamese-claimed territory in the Spratly and Paracel islands.
Vietnam and China have a long history of scrapes on the contested high seas, typically resulting in tit-for-tat diplomatic rhetoric.
The recent blowup has sparked a feverish response from Hanoi, which accuses Chinese boats of hindering its oil exploration activities within 200 nautical miles of its coast, which it claims as its exclusive economic zone. China dismisses the argument, saying the incidents occurred near territory it claims and that Vietnamese vessels endangered Chinese fishermen.
Associated Press writer Christopher Bodeen in Beijing contributed to this report.