BEIJING Jun 10 (Reuters) - China accused Vietnam of "gravely violating" its sovereignty and endangering the lives of Chinese sailors in an escalating territorial dispute that has added to broader tensions over the South China Sea.
The Chinese Foreign Ministry spokesman Hong Lei issued the condemnation of Vietnam late on Thursday after Hanoi accused China of harassing a ship doing seismic surveys in the South China Sea, where the neighbours have rival territorial claims.
China has quarreled with both Vietnam and the Philippines in recent weeks over their competing maritime claims and although a military clash seems unlikely, the tensions could trouble regional diplomacy and possibly draw in the United States, which took up the issue last year.
Hong said China was the victim in the latest encounter in which a Chinese fishing boat became entangled with cables from the Vietnamese ship and was dragged along for over an hour.
"The Vietnamese ship put the lives and safety of the Chinese fishermen in serious danger," Hong said in a statement on the Chinese foreign ministry website (www.mfa.gov.cn).
He accused Vietnam of violating China's claim on the Spratly archipelago and nearby seas, which Vietnam also deems its own.
"It must be pointed out that by conducting unlawful oil and gas surveys in seas around the Wan-an Bank of the Spratly archipelago and by driving out a Chinese fishing vessel, Vietnam has gravely violated China's sovereignty and maritime rights," said Hong.
"China demands that Vietnam cease all violations," he said, adding that Vietnam should "not take actions that would complicate and expand the dispute."
China, the Philippines, Malaysia, Brunei and Taiwan all claim territory in the South China Sea, parts of which could hold deposits of oil and gas .
China's claim is by far the largest, forming a vast U-shape over most of the sea's 648,000 square miles (1.7 million square km), including the Spratly and Paracel archipelagos.
The United States, the dominant military power in the Pacific with bases in Japan and South Korea, became embroiled in the sea tensions with China last year after Washington stressed its support for a collective regional solution to the mosaic of territorial disputes.
Beijing favours dealing with each dispute separately with the other countries staking territorial claims.
On Thursday, Vietnam said China had harassed its survey ship in the second such incident in two weeks, and it gave a very different account of the latest incident.
A Chinese fishing boat used a "cable cutting device" which became trapped in underwater cables used by a ship hired by Vietnam, the Vietnamese Foreign Ministry said. The ship was operating over Vietnam's continental shelf and within its exclusive economic zone off the southern coast, it said.
Two Chinese ships then came to help the Chinese fishing vessel, she said, calling the incident part of a campaign of systematic and intentional violations by China.
Vietnam lodged a complaint with China in late May when a Chinese patrol vessel slashed the cables of a Vietnamese ship conducting a seismic survey off its south-central coast.
China and the Philippines have also been exchanging accusations over rival claims over different parts of the Spratly islands.
Manila has accused China of intrusions into its territory, citing six instances, including one in March when two Chinese patrol boats tried to ram a survey ship. (Reporting by Chris Buckley; Editing by Sanjeev Miglani)