PHNOM PENH: Three notorious Cambodian torture and execution sites used by the Khmer Rouge to perpetrate genocide 50 years ago were inscribed on Unesco`s World Heritage List on Friday.

The hardline group, led by Pol Pot, reset the calendar to `year zero` on April 17, 1975, and emptied cities in a bid to create a pure agrarian society free of class, politics or capital.

Around two million people died of starvation, forced labour or torture or were slaughtered in mass killings between 1975 and 1979.

The Cambodian locations entered into the Unesco register include two prison sites and a `killing field` where thousands were executed.

`May this inscription serve as a lastingreminder that peace must always be defended,` Prime Minister Hun Manet said in a video message aired by staterun television TVK.

`From the darkest chapters of history, we can draw strength to build a better future for humanity.

Two sites added to the list are in the capital Phnom Penh _ the Tuol Sleng Genocide Museum and the Choeung Ek Genocide Centre.

Tuol Sleng is a former high school which was converted into a notorious prison known as S-21, where an estimated 15,000 people were imprisoned and tortured. Today the site is a space for commemoration and education, housing the black-and-white mugshots of its many victims.-AFP