Disputes over the South China Sea often provoke feelings of déjà-vu. That was especially the case this week, when Vietnam accused a Chinese ship of deliberately cutting exploration cables that were being towed by a seismic survey vessel working for PetroVietnam, the state-run oil and gas group. Vietnam says the June 9 incident occurred within the 200-mile continental shelf, in which it possesses economic rights under the 1982 U.N. Convention on the Law of the Sea.

China responded that Vietnam had provoked the encounter with Chinese fishing boats, which were working in waters where they had operated “for generations,” according to a written statement by Chinese Foreign Ministry spokesperson Hong Lei. Vietnamese ships were chasing away the Chinese fishing boats when one became tangled with the array towed by the PetroVietnam survey vessel, Hong said. He accused the Vietnamese of endangering the lives of the Chinese fishermen, and said that Vietnam’s oil and gas exploration “grossly infringed” on China’s sovereignty.

If this scuffle sounds familiar, it’s for good reason.The Vietnamese government says that on May 26 a Chinese surveillance vessel cut the survey cables of another Vietnamese survey ship. Vietnam’s defense minister complained about that incident during the Shangri-La security summit in Singapore last weekend. Anti-Chinese protests were held in Hanoi and Ho Chi Minh City, and in recent days several Vietnamese and Chinese websites have been reported hacked and defaced with nationalist messages.

Vietnam and China have fought multiple skirmishes for control of South China Sea. In 1974 China forced Vietnam from the Paracels in the northern part of the sea. And in 1988 the two sides fought over the southerly Spratlys, control of which remains divided between multiple claimants. Brunei, China, Malaysia, the Philippines, Taiwan and Vietnam all claim at least some part of the South China Sea. The region is rich in oil and gas deposits and also a thoroughfare for a significant portion of the world’s ship-borne trade.

Tensions between China and the Philippines have also heightened in recent weeks over disputed South China Sea claims. The Philippines has recently complained about Chinese naval ships in disputed waters and sent military aircraft to an area known as Reed Bank in March after Chinese vessels harassed a Philippines survey ship. On Thursday Liu Jianchao, the Chinese ambassador to the Philippines, warned countries in the region to stop searching for undersea resources “in these areas where China has its claims,” and denied any harassment of Philippine ships. He said that Chinese activities in the area were “part of our exercise of jurisdiction,” the Associated Press reported.

In 2002 the rival claimants agreed to resolve their disputes over the South China Sea peacefully. But little progress had been made since then. Last year Secretary of State Hillary Clinton said the U.S. would help mediate talks. That angered China, which wants to keep any discussions limited to the rival claimants. But Clinton’s comments may have emboldened some states, particularly Vietnam, to stand up to China. During the Shangri-La summit outgoing U.S. Defense Secretary Robert Gates expressed concern about rising tension in the South China Se, and that without further agreements among regional claimants disputes were likely to continue. “I feel that without rules of the road and without agreed approaches to dealing with these problems there will be clashes,” Gates said.