PARIS (AFP) - A half century after the United States plunged into war in Vietnam, scars remain unhealed. With a 10-part television epic, Ken Burns is hoping for a fuller understanding.

The celebrated documentary film-maker has invested 10 years into making The Vietnam War which aims to offer a more balanced view on the conflict by bringing in a wide range of American and Vietnamese voices.

"In many ways, the Vietnam War was our second civil war," said Burns, who won awards for his 1990 documentary on the 1861-65 US Civil War.

"I think that in the US, Vietnam is still very unsettled, and a source of a great deal of division. And I think so too in Vietnam," he added.

The series, set to a hypnotic score by members of industrial rockers Nine Inch Nails, started to air on Sunday on US public broadcaster PBS.

Burns, who co-directed The Vietnam War with Lynn Novick, called the US$30 million (S$40 million) project - reviewed at all stages by two dozen historians - the most ambitious of his career.

He noted that the television epic was "in some ways like a Russian novel, an epic sweep across generations with lots of primary characters, secondary and tertiary characters".

"Courage could not always be on the battlefield," he said.

"It could be the decision not to go to war, to protest that war."

But also, most importantly, was including "the voices of the Vietnamese, both our enemies and our allies, civilians, and to have a much fuller multi-dimensional portrait".

According to the Vietnamese government, more than three million civilians died over the span of the war along with more than 2.5 million troops fighting for both the triumphant communist North and the US-allied South.

US official figures say 200,000 South Vietnamese and 58,200 US soldiers died.