A front page editorial in the Nhan Dan newspaper eulogised the party's key role in reunifying the country and said only it could ensure Vietnam's future prosperity by adapting the lessons of the past to the future.

"The party's leadership was the vital factor in the success of the liberation war in the past and it will decide the success of the country's process to socialism today," the party mouthpiece said.

"To realise the new revolutionary mission, our party has to regularly reform, reconstruct and rectify," it added.

Dates marking important milestones in Vietnam's struggle against foreign occupation are always used as a means to remind the population of the party's instrumental hand in securing ultimate victory.

Reunification of North and South Vietnam on April 30, 1975, brought an end to more than 30 years of continual warfare which cost the lives of more than three million Vietnamese.

But the party, which has ruled the country with an iron rod since then, is today struggling to maintain its legitimacy and relevance in the face of widespread discontent over corruption and the impact of external influences on both society and the economy.

No formal celebrations took place Wednesday, a public holiday, but more than 1,200 dignitaries, including retired generals and former party heads, attended a ceremony on Tuesday in the capital to mark Reunification Day.

While Communist Party founding father Ho Chi Minh died in 1969, the liberation of Saigon -- renamed Ho Chi Minh City the following year -- was the culmination of the struggle he led against the Japanese, French and Americans.

The United States, which had pulled its forces out of South Vietnam in 1973 under the Paris Peace Accord after a 25-year presence, could do nothing as North Vietnamese troops began their blitzkrieg in the South in January 1975.

Saigon's fall, symbolised by frantic footage of helicopters evacuating US personnel and well-connected South Vietnamese from the roof of the US embassy, dealt a lasting blow to the collective psyche of the Cold War superpower.

The United States first became involved in Vietnam in 1944 when it funded and supplied arms to Ho Chi Minh against the Japanese.

At the end of the World War II it then bankrolled France's attempts to restablish control over its colony as part of Washington's global struggle to contain the spread of commumism.

However, the 57-day siege of Dien Bien Phu, in which more than 10,000 French troops surrendered on May 7, 1954, became a portent for the next two decades of fighting against a fierce, determined peasant army.

It also led to the Geneva Accords that split the country into two zones ahead of nationwide elections that were due to be held in July 1956 but which the South Vietnamese regime refused to hold, fearing defeat.

The first US military advisers had arrived on Vietnamese soil in 1950 and their numbers rapidly increased following the pullout of the last French troops in April 1956.

Washington finally took the "advisory" gloves off in March 1965 when the first US combat troops splashed ashore at Danang.

Come the final humiliation, its Vietnam foray cost the United States the lives of more than 58,000 Americans.

SPACE.WIRE