The convicted man, Nuon Paet, is the first senior Khmer Rouge leader to have faced trail in Cambodia.

Briton Mark Slater, Australian David Wilson, Frenchman Jean Michele Braquet and 13 Cambodians were abducted from a train travelling to Cambodia's south coast during an ambush by Khmer Rouge troops in the summer of 1994.

Ten Cambodians were killed during the attack on the train.

The foreigners, all in their twenties, were killed several months later, after negotiations for their release broke down.

'Under orders'

Nuon Paet says the killings were ordered by his superiors

Nuon Paet, told the court in the Cambodian capital, Phnom Penh, that the killings were ordered by his superior, Sam Bith, who is now an army general.

The prosecutor said he had received cabinet approval to charge the general and another former Khmer Rouge commander, Chouk Rin, if sufficient evidence emerged from the trial.

The two men were in the courtroom at the time having been summoned as witnesses in the case against Nuon Paet.

The trial has been seen as an important test case for the Cambodian judicial system and the ability of the courts to act impartially and independently.

Fresh concerns over fairness have been raised because of the brevity of the trial. Proceedings lasted less than a day.

Reign of terror

Two other senior Khmer Rouge leaders, military chief, Ta Mok, and the former head of the movement's secret police, Duch, are under arrest awaiting trial.

Others however are living freely within Cambodia under surrender deals negotiated with the government.

An estimated 1.7 million people were killed during the movement's reign of terror.

The BBC's Phnom Penh Correspondent Caroline Gluck says international legal experts doubt that the Cambodian courts are up to the job of trying the group's former leaders.

The government, which has rejected an international tribunal, has asked the UN to help in drafting a law to create a special tribunal.

This would allow for foreign judges and lawyers to participate in trials of Khmer Rouge leaders in a Cambodian court.