The man in charge of a Khmer Rouge detention center has gone on trial for alleged war crimes, in the first prosecution from the 1970s reign of terror in Cambodia.
Kaing Guek Eav, known as Duch, went on trial Tuesday for war crimes, crimes against humanity, torture and murder. Duch was head of the S-21 detention center where more than 12,000 Cambodians were executed after being accused of disloyalty to the Khmer Rouge.
Duch has confessed that he committed atrocities and has asked for forgiveness.
An estimated 1.7 million people died at the hands of the Khmer Rouge regime.
The joint Cambodian - United Nations court will put at least five Khmer Rouge officials on trial.
Human rights advocates say more people should be prosecuted, but Cambodian officials have been reluctant to increase the number of trials.
The communist Khmer Rouge controlled Cambodia between 1975 and 1979. Under its leader Pol Pot, the Khmer Rouge attempted to create what it called a communist utopia.
City dwellers were forced into the countryside and anyone who looked educated or was accused of disloyalty was tortured and often executed.
The Khmer Rouge was ousted when Vietnam invaded in 1979.