PHNOM PENH: Cambodia`s UN-backed war crimes court on Monday gives its verdict on the Khmer Rouge prison chief, in a step towards justice for the "Killing Fields" atrocities more than three decades ago.

Kaing Guek Eav, better known as Duch, used his trial to apologise for his role in the brutal communist regime that killed up to two million people, but he shocked the court in final arguments with a demand for acquittal.

"If he gets 40 years in prison, which is what the prosecution asked for, then I think the Cambodian people will be satisfied," said anthropology professor Alex Hinton, who is researching Cambodia`s reaction to the trial.

For Cambodians, the controversial tribunal, established after nearly a decade of negotiations between Cambodia and the United Nations, is the last chance to find justice for the Khmer Rouge`s crimes during its 1975-1979 rule.

Since his trial began in February last year, Duch, 67, publicly asked for forgiveness for overseeing the murders of around 15,000 men, women and children at Tuol Sleng prison, built in a former high school.

But the former maths teacher, one of five senior members of the communist movement detained by the court, surprisingly asked to be released in the final day of hearings on grounds he was not a key leader in the regime.

He is charged with crimes against humanity, war crimes, torture and premeditated murder, and faces a maximum term of life in prison by the tribunal, which does not have the power to impose the death penalty.

Few expect judges to take his acquittal demand seriously, although analysts speculate he will appeal his sentence after it was announced this month he had sacked his French lawyer Francois Roux for "lack of confidence".

Duch will continue to be represented by his Cambodian lawyer, Kar Savuth, as hundreds of Cambodians are set to attend the specially built courtroom on the outskirts of Phnom Penh for the hearing, due to start at 10:00 am (0300 GMT).

Duch will sit with judges and lawyers behind a massive bulletproof window to prevent possible revenge attacks.

The verdict is being broadcast live by all Cambodian television and radio stations.

Tuol Sleng, also known as S-21, was the centre of the Khmer Rouge security apparatus and thousands of inmates were taken from there for execution at nearby Choeung Ek, an orchard that served as a "Killing Field".

Led by "Brother Number One" Pol Pot, the Khmer Rouge was responsible for one of the worst horrors of the 20th century, wiping out nearly a quarter of the population through starvation, overwork and execution.

Rising to power as a tragic spin-off of the US conflict in Vietnam, the movement emptied Cambodia`s cities to take society back to a rural "Year Zero," purging city dwellers, intellectuals and even people who wore glasses.

The Khmer Rouge was ousted by Vietnamese-backed forces in 1979, but continued to fight a civil war until 1998. Pol Pot died in the same year.

Duch has been detained since 1999, when he was found working as a Christian aid worker in the jungle, and was formally arrested by the tribunal in July 2007.

The court has faced controversy over allegations of interference by the government and claims that Cambodian staff paid kickbacks for their jobs.

The joint trial of four other more senior Khmer Rouge leaders charged with genocide is expected to start in 2011.

The court is also investigating whether to open more cases against five other former Khmer Rouge cadres after a dispute between the international and Cambodian co-prosecutors over whether to pursue more suspects.

BDST: 0928 HRS, July 26, 2010