he Vietnamese government has agreed to hand over 16 documentary films about the Khmer Rouge to the Documentation Center of Cambodia, which help in the prosecution of leaders of the regime, officials said Friday.

The film donation marked a first among Asean countries in aiding the tribunal, which is preparing for the first trial of five jailed leaders in early 2009.

The films, which include English and Khmer language, were shot by Vietnamese soldiers between 1977 and 1982 and document several aspects of the regime: conditions for children, criminal evidence against Pol Pot in Prey Veng province, Tuol Sleng in 1979, the treatment of foreigners and the killing of Vietnamese nationals in Vietnam's Tai Ninh province.

"This is an indictment of war crimes," said Youk Chhang, director of the Documentation Center, as he prepared to travel to Hanoi Friday to pick up the films. "These documents are very important. They show a step forward in what was a clash between the Khmer Rouge and Vietnamese troops. And some of the documentaries are related to information that can serve as evidence that has not been use or analyzed yet."

Ethnic Vietnamese suffered heavily under the Khmer Rouge, and hundreds were killed in Tuol Sleng, the prison headed by Duch, who is scheduled to be the first leader of the regime to face trial.

"I think these documents will serve for research on the genocide of the past," said Trinh Ba Cam, a spokesman for the Vietnamese Embassy in Phnom Penh.

He did not comment on the reason behind the donation, but Youk Chhang said Friday it was likely due to the killings of Vietnamese soldiers and residents, as well as the independent nature of his documentation center.

Tribunal spokesman Reach Sambath said the films were "valuable for theevolution" of the courts, which have already used many of thedocuments gathered by Youk Chhang and his researchers over more theyears.