It will be only the second visit by Vietnamese officials to a passing US carrier. The visit - geared to mark the 15th anniversary of the normalisation of US-Vietnamese diplomatic ties - will be followed by the arrival in Danang early next week of one of the strike group's destroyers.

Officers from that ship, the USS John S. McCain, will take part in training exchanges between the two navies that will see the two sides explain internal procedures for non-sensitive operations, such as firefighting and search and rescue.

'It is the first time we have had these kind of two-way training exchanges,' said Lieutenant Mike Morley of the US Navy's Singapore-based Task Force 73. 'We see them as a good way of building positive friendships and trust.'

The destroyer is named after the father and grandfather of John McCain, the US senator and failed presidential contender who is a respected figure in Vietnam. He was held and tortured in Hanoi after being captured as a fighter pilot during the Vietnam war, and has returned repeatedly in recent decades to urge a new era in ties between the two countries.

The US and Vietnam were at war for more than a decade, and remained suspicious of each other for years afterwards. Their emerging military relationship is closely scrutinised, reflecting Hanoi's alarm at China's assertiveness in the South China Sea and Washington's attempts to re-engage with Southeast Asia.

The Pentagon now classes Vietnam as a potential strategic partner, along with Indonesia and Malaysia.

News of the visit comes only a fortnight after US Secretary of State Hillary Rodham Clinton told the region's top security conference in Hanoi that peacefully solving South China Sea disputes was a US 'national interest' and 'diplomatic priority'.

While Clinton kept to the US tradition of not taking sides on the rival claims in the area, she called for a multilateral solution - backing Southeast Asian claimants and apparently countering China's demand that disputes be solved by individual countries dealing directly with Beijing.

Chinese officials told White House counterparts in March that Beijing considered the South China Sea a 'core interest' - diplomatic code that makes it as sensitive as Taiwan and Tibet.

Danang is the closest Vietnamese port to the Paracel islands, south of Hainan, which are occupied by China. Chinese vessels attempted to block a US military oceanographic research ship in February last year in waters between Danang and Hainan.

China and Vietnam claim the Paracel and Spratly archipelagos in their entirety; Malaysia, Brunei and the Philippines claim them in part.

China claims virtually the entire South China Sea as its exclusive economic zone - something PLA officials insist gives them the right to object to surveillance by foreign militaries.

The Pentagon, meanwhile, insists any such zone is still international waters, giving it the right to routine military activity, which includes surveillance. Carrier strike groups operate a surveillance web over vast areas of water to protect the carrier.

Officials have also told the US Congress that challenges to US rights in international waters would be met with a carefully calibrated increase in patrols - something the presence of the George Washington strike group appears to reflect. Analysts expect to see a growing pattern of visits to Vietnamese ports by US and other naval ships, including from regional powers such as India, Russia and Japan.

A US naval supply ship was repaired at a Vietnamese shipyard near the highly strategic Cam Ranh Bay earlier this year and a services agreement to formalise such work - generally carried out only by US allies and friends - is now under discussion.