The head of state-run energy giant PetroVietnam has attempted to hose down reports that Chinese fishing vessels deliberately sabotaged cables of a seismic ship in Vietnam-controlled waters of the South China Sea, calling the incident an accident.
"China cut the cables by accident," Do Van Hau, CEO of PetroVietnam, said. "It's unlike last time when they intentionally cut our cables."
PetroTimes, a newspaper run by the company, had earlier quoted Pham Viet Dung, deputy head of exploration, of accusing the fishing vessels of "harassing" the Binh Minh 2 survey ship when the cables were cut last Friday. The cables were later repaired.
The boats "ran up behind the Binh Minh 2, cutting the Vietnamese ship's seismic cables ... Many Chinese vessels were operating in the area", Dung was quoted as saying in Monday's PetroTimes.
Dung said PetroVietnam objected to the Chinese boats' actions in Vietnamese territorial waters and said Hanoi must "ask Chinese citizens to respect Vietnam's sovereignty".
China's foreign ministry was still "verifying the situation", spokesman Hong Lei said. The incident took place in waters claimed by both countries, he said, and "Chinese fishing boats were engaging in normal fishing activity in that part of the sea".
This is the second such incident in 18 months, with Chinese vessels accused of cutting the cables of the Binh Minh 2 in May last year, prompting Hanoi to demand compensation from Beijing.
The South China Sea is strategically significant as it contains some of the world's most important shipping lanes and is believed to be rich in resources. Vietnam has begun exploring for oil in what it claims as its territorial waters.
The two countries have a long-standing dispute in the South China Sea over their competing claims to the Paracel (called the Xisha Islands by China and the Hoang Sa Islands by Vietnam) and the Spratly islands (called the Nansha Islands by China) both potentially resource-rich rocky outcrops that straddle key shipping lanes.
Last week, Vietnamese border guards said they were refusing to stamp entry visas into China's controversial new passports which feature a map of Beijing's claim to almost all of the South China Sea.
Earlier this year, PetroVietnam warned China to halt efforts to develop disputed areas of the South China Sea that Hanoi's leaders have already awarded to companies including Exxon Mobil and OAO Gazprom. China National Offshore Oil, the government-owned parent of Cnooc, deployed China's first deep-water drilling rig in May near disputed islands.