<P> The Khmer Rouge period (1975--1979) refers to the rule of Pol Pot, Nuon Chea, Ieng Sary, Son Sen, Khieu Samphan and the Communist Party of Kampuchea over Cambodia, which the Khmer Rouge renamed Democratic Kampuchea . </P> <P> A four - year period cost approximately 2 million lives through the combined result of political executions, disease, starvation, and forced labor . Due to the large numbers, the deaths during the rule of the Khmer Rouge are commonly known as the Cambodian Holocaust or Cambodian genocide . The Khmer Rouge took power at the end of the Cambodian Civil War and were only toppled after the invasion of Cambodia by the neighbouring Socialist Republic of Vietnam in the Cambodian--Vietnamese War . Most of Cambodia remained under Vietnamese occupation for over a decade . </P> <P> By the 17 April 1975 Khmer Rouge victory, Pol Pot and his associates occupied the most important positions in the Communist Party of Kampuchea (CPK) and in the state hierarchies . Pol Pot had been CPK general secretary since February 1963 . His associates functioned as the party's Political Bureau, and they held a majority of the seats on the Central Committee . </P> <P> Through the 1970s, and especially after mid-1975, the party was shaken by factional struggles, including armed attempts to topple Pol Pot . Punitive measures resulted in 1977 and 1978 when hundreds of thousands of people, including some of the most important CPK leaders, were executed . </P>

Who took power in cambodia and what did they do