Workers building a house for a Buddhist monk in Cambodia have discovered the remains of 18 people believed to have been killed by the Khmer Rouge.

Laborer Nhoung Snieng said Tuesday that they started finding the remains, some shackled, when they began digging last week at Kes Sararam temple in the northwestern province of Siem Reap.

The temple's chief monk, Sambath Ly Yeath, said the site had been a Khmer Rouge prison when the ultra-communist group ruled Cambodia between 1975 and 1979. An estimated 1.7 million people died under the regime.

Siem Reap is famous for its centuries-old Angkor temple complex. The most notorious Khmer Rouge prison was the Tuol Sleng torture center in Phnom Penh, but the group maintained around 200 prisons nationwide.