China defended its ties with Cambodia's Khmer Rouge regime saying it was part of normal diplomatic relations, as a trial began on Tuesday in Phnom Penh of the group's chief torturer.
The Khmer Rouge are blamed for the deaths of 1.7 million people during their 1975-79 reign of terror in which many of their victims were tortured and executed. The rest died of disease, starvation or exhaustion.
"For a long time China has ... had normal and friendly relations with previous Cambodian governments, including that of Democratic Kampuchea," said Chinese Foreign Ministry spokeswoman Jiang Yu, refering to the former Khmer Rouge government.
"As everyone knows, the government of Democratic Kampuchea had a legal seat at the United Nations, and had established broad foreign relations with more than 70 countries," she told a regular news conference.
Kaing Guek Eav, known as Duch and ex-commandant of the notorious S-21 prison, went on trial for crimes against humanity on Tuesday, the first case involving a senior cadre three decades after the end of the Khmer Rouge regime.
Duch has admitted atrocities at S-21, the former school where up to 14,000 "enemies of the revolution" were tortured before being beaten to death in the "Killing Fields" outside Phnom Penh.
China had close relations with the Khmer Rouge and its leader Pol Pot. Beijing, still a major donor and investor in Cambodia, has pledged no money to the court, but has taken no active steps to block the trial.
"The trial of former Democratic Kampuchean leaders is an internal political matter for Cambodia," Jiang said. "We hope international society can respect the choices of the Cambodian government and people."