Vietnam and the United States appear to be making slow but steady steps to expand their simple commercial ties to a more pragmatic, military one.

On Thursday, US Secretary of Defense Donald Rumsfeld invited his Vietnamese counterpart, Pham Van Tra, to visit the United States.

"If the visit takes place, it will be the first to the U.S. by a Vietnamese defense minister (since the end of the Vietnam war)," said foreign ministry spokesman Le Dung in Hanoi.

The timing and agenda of the visit are still to be decided.

The visit would also reciprocate a visit by former U.S. defense secretary William Cohen, who made a three-day trip to Vietnam in March 2000.

"Over the past years, the political and diplomatic relations between the two countries have been enhanced. That's why there are increasingly numerous exchanges of visits between the two countries at various levels, ministries and agencies,” says Mr. Dung.

However, there are still elements of suspicion within Hanoi over Washington's motives, especially with Vietnam having been a vocal opponent of US military action against Iraq. Hanoi and Washington have also recently expressed loud disagreement on human rights issues.

MIA Issue

Notably, there has been significant progress in the extremely sensitive missing in action issue.

Last week, Vietnam agreed to give the United States some access to top secret files in an effort to gather information about Americans who may have been held captive after the Vietnam War.

Officials in Hanoi have always insisted that no Americans were held after the war.

It is estimated that around 1,900 Americans and 300,000 Vietnam's victims are still listed as missing.