A tentative agreement has been reached between the US Pentagon and the ministry for the visit to Washington by the general, who is a member of the Communist Party's elite 15-member Politburo, a US source said.

Plans have also been drawn up for Admiral Thomas Fargo, commander of the US Pacific Command, to visit Hanoi, and for the frigate USS Gary to make a port stop in Ho Chi Minh City in November, he said, requesting anonymity.

The US embassy in the Vietnamese capital said it was unable to confirm or deny the information. "We don't comment on such visits," a spokesman said.

The Vietnamese government could not be immediately contacted for comment.

Analysts say that if Tra's visit goes ahead it could mark a significant change in policy within the ranks of Vietnam's conservative military towards its former sworn enemy.

It would also reciprocate a visit by former US defence secretary William Cohen, who made a three-day trip to Vietnam in March 2000 in a bid to develop a military-to-military relationship.

He was the first defense chief to visit the Southeast Asian nation since the end of the Vietnam War in 1975, which resulted in the deaths of over 58,000 Americans and around three million Vietnamese.

"Tra's trip would be very significant on the defence side of the bilateral relationship which has been markedly undeveloped," said Carl Thayer, a long-time Vietnam watcher at the Australian Defence Force Academy.

"This has long been on the cards. The Vietnamese owe a return visit by Cohen and are now doing so at a time when US is dominant in the region with its the war on terrorism."

Thayer cautioned that for the visit to take place both sides would have "to feel that something concrete will emerge from it in terms of greater military-to-military cooperation between the two countries".

Currently, military relations between the two countries revolve around the search for US personnel missing in action (MIAs) from the war and other humanitarian programmes, such as medical and demining training.

"Tra's visit would shift the major focus of the relationship away from the traditional focus on MIAs and move it to new areas," Thayer said.

Tra, who was appointed defence minister in 1997, would not, however, be the first high ranking military officer to visit the United States.

In October 1998 Lieutenant-General Tran Hanh visited Washington and held talks with Cohen, while in September the following year a colonel travelled to the US capital on a MIA archival research mission.

Formal US-Vietnam diplomatic relations were only established in 1995, a year after then-president Bill Clinton lifted a trade embargo on the country.

Despite burgeoning bilateral trade ties, relations remain lukewarm with Hanoi particularly suspicious of what it considers Washington's imperialist global foreign policy.

Thayer warned that Hanoi would most probably cancel the planned visits if the US government initiated military action against Iran or tried to throw its weight about in a different arena.

"Vietnam would not want to associate itself with such actions," he said.

Hanoi was a fierce critic of the US-led strike on Iraq earlier this year.

WAR.WIRE