Cambodian Prime Minister Hun Sen warned yesterday that putting more Khmer Rouge cadres on trial for crimes committed during Pol Pot's 1975-79 rule could plunge the country back into civil war.

"I would prefer to see this tribunal fail instead of seeing war return to my country," Hun Sen, himself a former Khmer Rouge commander, said a day after the joint UN-Cambodian court resumed its trial of Pol Pot's prison chief.

Duch, former head of the S-21 prison where more than 14,000 "enemies" of the ultra-leftist revolution reportedly died, is the first of five ageing senior cadres to face trial 30 years after the end of Pol Pot's rule blamed for 1.7 million deaths in Cambodia.