The three most senior surviving leaders of Cambodia’s Khmer Rouge have gone on trial at a UN-backed tribunal.
Nearly two million people died under Pol Pot’s regime over three decades ago.
The three are on trial for crimes against humanity and genocide.
Pol Pot’s right-hand man Nuon Chea, ex-president Khieu Samphan and former foreign minister Ieng Sary deny the charges.
Former Cambodian social affairs minister, Ieng Thirith, has been declared unfit to face trial.
The tribunal was hit last month by one judge’s resignation, who alleged political interference.
The Khmer Rouge ruled Cambodia from 1975 to 1979.
Its leader Pol Pot wanted to impose a communist agrarian state by forcing people to live and work on collective farms.
An estimated one-quarter of the population died — victims of execution, starvation and torture.
Pol Pot died in the jungle in 1998.