Students staged a re-enactment of Khmer Rouge crimes at one of Cambodia's notorious "killing fields" Wednesday as about 2,000 people marked the annual "Day of Anger" for those killed by the regime. 

 The crowd, including more than 200 Buddhist monks, mimed bludgeoning, strangling and eviscerating bound victims at Choeung Ek, outside the capital Phnom Penh. 

Dozens of black-clad students attended the rally held close to mass graves where Khmer Rouge soldiers murdered thousands of people. 

"This is to remind the world that this kind of regime will never happen again and that those perpetrators must be brought to justice," Phnom Penh governor Kep Chuktema said in a speech during the ceremony.

Many attending Wednesday's performance were moved to tears and called for speedier trials of former Khmer Rouge leaders currently being held by the UN-backed war crimes court.

"I demand that the trial of Khmer Rouge leaders be completed very soon so that we can see the faces of those who killed Cambodian people," said 71-year-old regime survivor Chhuon Chhor. 

UN and Cambodian officials at the tribunal said in a press conference that the court's first trial would finish before the end of this year. 

The trial against former Khmer Rouge prison chief Kaing Guek Eav, better known as Duch, began in February. He has admitted to overseeing executions, but denies personally killing anyone. 

Duch is one of five surviving Khmer Rouge leaders detained by the court on charges of crimes against humanity and war crimes, with proceedings against the other suspects expected to begin within the next year. 

Up to two million people died from starvation, overwork, torture and execution during the communist regimes 1975-1979 reign as it emptied Cambodia's cities and enslaved the population on collective farms.