Pol Pot reformed Cambodia as a new , one-party state called Democratic Kampuchea . Seeking to create an agrarian socialist society , his government forcibly relocated the urban population to the countryside to work on collective farms . Those regarded as enemies of the new government were killed . These mass killings , coupled with malnutrition , strenuous working conditions and poor medical care , killed between 1.5 and 3 million people , approximately a quarter of Cambodia 's population , a period later termed the Cambodian genocide . Marxist – Leninists unhappy with Pol Pot 's government encouraged Vietnamese intervention . After Pol Pot attacked several Vietnamese villages , the Vietnamese invaded Cambodia in December 1978 , toppling Pol Pot 's government in 1979 . The Vietnamese installed a rival Marxist – Leninist faction opposed to Pol Pot and renamed the country the People 's Republic of Kampuchea . Pol Pot and his Khmer Rouge retreated to a jungle base near the Thai border . Until 1993 , they remained part of a coalition internationally recognized as Cambodia 's legitimate government . The Ta Mok faction placed Pol Pot under house arrest , where he died in 1998 , possibly from suicide
Cambodian genocide
Cambodian genocide
Pol Pot