The United Nations and Cambodia are set to sign an historic document that paves the way for a trial of surviving Khmer Rouge leaders blamed for the deaths of up to two million people.
The document -- to establish extraordinary legal chambers -- is expected to be signed by United Nations legal counsel Hans Corell, who arrived here late Thursday, and his Cambodian counterpart Sok An.
Prime Minister Hun Sen said in a national broadcast that people had died every day under Pol Pot's regime, but that Cambodian life had changed dramatically in the past two decades.
The trial will help put an end to the Khmer Rouge issue, he said.
"We have changed -- from the sounds of crying to the sounds of chanting monks and learning," Hun Sen said.
"We have turned from an extremely difficult situation and reached a full peace."
Under the extreme left regime, religion and music were outlawed, education stopped and intellectuals were allegedly slaughtered.
"These developments mark a major step forward in the long and difficult process of coping with Cambodia's tragic past," said Youk Chang, Director of Documentation Center of Cambodia which collates evidence of crimes committed under Pol Pot.
He said the trial would help end Cambodia's notorious culture of impunity which was cited by the UN as one reason for an initial withdrawal.
Scholars have cited at least eight former high-ranking former Khmer Rouge leaders for trial. Charges include genocide and crimes against humanity, allegedly committed between April 17, 1975, and January 7, 1979.
Two of Pol Pot's henchmen -- former military commander Ta Mok, and Kang Kek Ieu, also known as Duch, who ran the S21 torture and execution centre -- are languishing in a Phnom Penh jail awaiting trial.
The remaining five live freely in Phnom Penh and Cambodia's remote west near the Thai border, where they have denied the allegations and called for a Truth and Reconciliation Commission.
Last December, former prime minister Khieu Samphan and former Brother Number Two, Nuon Chea, said they would testify before a Truth and Reconciliation Commission if granted immunity from prosecution.
"At a trial, people would not understand," Khieu Samphan told AFP in a rare interview. "And we can't afford a defence and therefore we won't get a fair trial."
The pair are neighbours and live in modest Cambodian-stilted homes outside of north-west provincial town of Pailin, metres (feet) from the Thai border.
Former foreign minister Ieng Sary and his wife Ieng Tirith have also been cited for trial. The couple are based in Phnom Penh. Two military divisional chiefs, Sou Met and Meas Muth, have also been listed.
Former leader Pol Pot died in 1998.
The signing of the document will end marathon negotiations characterised by mistrust on both sides that culminated in the UN pulling out of the stormy process in February, 2002.
The world body only re-entered talks with the Cambodians after members of the General Assembly passed a resolution instructing the UN's office of legal affairs to press ahead with establishing the tribunal.
Once signed, the document must pass into law through Cambodia's Parliament, however this is not expected until after the July 27 elections.
Sources close to negotiations said they were hopeful a trial would be underway by December this year.