PHNOM PENH (Reuters) - The chief Khmer Rouge torturer went on trial for crimes against humanity on Tuesday, the first senior Pol Pot cadre to be tried by the “Killing Fields” court three decades after the deaths of 1.7 million Cambodians.

Kaing Guek Eav, alias Duch and ex-commandant of the notorious S-21 prison, did not address the court, but sat impassively as lawyers haggled over procedural matters.

Hundreds of victims, including saffron-robed Buddhist monks who were persecuted during the 1975-79 Khmer Rouge era, packed the public gallery, reacting with anger and relief at the sight of 66-year-old Duch in the dock.

“This is the day we have waited for 30 years,” said Vann Nath, 63, one of a handful of survivors from S-21 where at least 14,000 “enemies of the revolution” were tortured and killed.

This week’s hearings will lay the groundwork for a full-blown trial in March, when Duch and survivors are expected to testify.

Duch, now a born-again Christian, has expressed remorse before facing the joint Cambodian-U.N. tribunal, set up to prosecute “those most responsible” for one of the darkest chapters of the 20th century.

“Duch wishes to ask forgiveness from the victims and the Cambodian people. He will do so publicly,” French defense lawyer Francois Roux told reporters at the specially built court outside the Cambodian capital.

The trial is a landmark for the strife-torn country where nearly everyone lost loved ones in the violence, starvation and disease that followed Pol Pot’s dream of an agrarian utopia.

It also ends a decade of wrangling over jurisdiction and cash at the tribunal, which had left many Cambodians wondering if Pol Pot’s surviving henchmen would ever face a judge.

“Today is history and they hope the court will bring them justice,” said Hong Kim Suon, a lawyer representing victims.

The Extraordinary Chambers in the Courts of Cambodia, as the joint tribunal is known, has been called an “experiment in international justice,” with domestic and foreign judges working side-by-side to try to ensure its independence.

But critics say its integrity is threatened by allegations of corruption and political interference over who to prosecute.

“Any hint of political manipulation at the tribunal will undermine its credibility with the Cambodian people,” said Sara Colm, Cambodian-based senior researcher at Human Rights Watch.

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Four other Khmer Rouge cadres have been charged but a bid to go after more suspects was brushed aside last month by the tribunal’s Cambodian co-prosecutor, who said it would not help national reconciliation.

Cabinet spokesman Siphan Phay denied any meddling and said the government wanted to complete the trials of the five people already facing charges before going after other suspects.

“First things first,” he told reporters. “We have never said we opposed anything, but let’s finish these first.”

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YEAR ZERO

Duch also faces charges of war crimes, torture and homicide while chief of S-21, where at least 14,000 men, women and children passed through the barbed wire gates.

After being forced to confess to crimes, they were shot or beaten to death in the “Killing Fields” outside the capital.

Only 12 survived, according to the U.S.-funded Documentation Center of Cambodia, which has researched the Khmer Rouge era.

“Duch’s hands are full of blood. It’s time for Duch to pay for his actions,” said 39-year-old Norng Chan Phal, a child survivor of S-21 who is among survivors expected to be allowed to join the trial process.

Duch is one of five aging senior cadres charged for their roles in the “Year Zero” revolution that ended when a Vietnamese invasion forced the Khmer Rouge back into the jungles in 1979.

He is expected to be a key witness in the trials of “Brother Number Two” Nuon Chea, Khieu Samphan, who was the regime’s ex-president, and Ieng Sary, its foreign minister, and his wife.

These four have denied knowledge of any atrocities by the Khmer Rouge during its rule, which began by driving everyone out of the cities with whatever they could carry.

If convicted, the five could face life in prison.

Pol Pot’s death in 1998 was followed by a formal Khmer Rouge surrender which helped to usher in a decade of peace and stability, threatened now by the global economic downturn.