Former enemies Vietnam and the United States began a joint naval drill on Friday, despite Chinese objections after weeks of escalating tension in the disputed South China Sea.

US officials described the week-long exercises off Vietnam's central coast as "non-combatant events", focused on areas such as navigation and maintenance, in a statement from the consulate general in Ho Chi Minh City.

But China's top military officer General Chen Bingde said Monday that the timing of US naval exercises in the area was "inappropriate", after talks with his American counterpart Admiral Mike Mullen aimed at cooling the tensions.

China, the Philippines, Vietnam, Brunei, Malaysia and Taiwan all have overlapping claims to parts of the South China Sea, believed to be rich in oil and gas deposits and home to shipping lanes vital to global trade.

Vietnam and the Philippines have in recent months accused Beijing of taking increasingly aggressive actions in staking its claims in the sea.

Tensions flared in May when Vietnam said Chinese marine surveillance vessels cut the exploration cables of an oil survey ship.

Since then, a series of anti-China protests have been held in Vietnam, where rallies are rare, with the latest on Sunday being forcibly dispersed by local police. At least 10 people, including journalists, were briefly arrested.

During talks on June 25, Beijing and Hanoi promised to resolve the issue peacefully, and China has warned Washington not to get involved in regional maritime disputes, according to state media.

The US and Vietnam, former wartime enemies, normalised relations in 1995 and have been rapidly building relations across a wide range of areas, including military affairs.

"This exchange helps our respective sailors gain a greater understanding of one another and builds important relationships between our navies for the future," Rear Admiral Tom Carney said of the latest drill.

The Philippine and US navies also recently held 11 days of military exercises close to the South China Sea, war games that have been seen as aimed at recent Chinese provocations.

earlier related report
Police again break up anti-China demo in Vietnam
Hanoi (AFP) July 17, 2011 - Vietnamese police rounded up at least 10 people as they broke up an anti-China rally on Sunday for the second weekend running after a series of protests over tensions in the South China Sea.

Around 50 demonstrators, greatly outnumbered by security forces, were stopped and forced to disperse after they gathered close to the Chinese embassy in the capital Hanoi.

"Down with China! Down with arresting patriotic people!" shouted the protesters as they waved banners denouncing Chinese "violations" of Vietnamese sovereignty.

It was the seventh in an unprecedented series of protests -- uncommon in authoritarian Vietnam -- that have taken place in Hanoi on recent weekends during an escalating maritime dispute in the South China Sea.

Authorities in Hanoi allowed the first five protests to proceed without incident, but briefly detained 10 people, including journalists, during a rally on July 10 after talks with China in Beijing.

The communist neighbours have long been at odds over the potentially oil-rich Paracel and Spratly island groups, which straddle vital commercial shipping lanes in the South China Sea.

At their June 25 meeting, both sides agreed to resolve their territorial disputes peacefully. Beijing and Hanoi "also laid stress on the need to steer public opinion in the correct direction", the official Vietnam News said.

Human Rights Watch criticised the "latest wave of arrests and violence against peaceful demonstrators".

"These protesters should not have been arrested in the first place and the authorities should release them immediately without conditions," said Asia division deputy director Phil Robertson.

Tensions flared in May when Vietnam said Chinese marine surveillance vessels cut the exploration cables of an oil survey ship and Hanoi has accused its neighbour of harassing Vietnamese fishing boats in the disputed waters.

On Friday, Vietnam and the United States began a joint naval drill in the South China Sea despite Chinese objections.