and cadres out of Cambodia. Since the KPRP was staffed primarily by ethnic Vietnamese or Cambodians under its tutelage, approximately 5,000 communist cadres went with them. The power vacuum the Vietnamese communists left in their wake in Cambodia was soon filled by the return of a young group of Cambodian communist revolutionaries, many of whom received their education in France. In 1960, the KPRP changed its name to the Kampuchean Communist Party (KCP), and the name was later adopted by the majority coalition that formed around Saloth Sar (Pol Pot), Ieng Sary, and Khieu Samphan as the true political institution memorialising the KCP. This clique became the genesis of the Khmer Rouge, and its doctrine was heavily influenced by Maoist ideology. Lon Nol's anti-Vietnamese sentiment After the removal of Sihanouk from power in March 1970, the leader of the new Khmer Republic, Lon Nol, despite being anti-communist and ostensibly in the "pro-American" camp, backed the FULRO against all Vietnamese, both anti-communist South Vietnam and the communist Viet Cong. Following the 1970 coup, thousands of Vietnamese were massacred by forces of Lon Nol. Many of the dead were dumped in the Mekong River. 310,000 ethnic Vietnamese fled Cambodia as a result. The Khmer Rouge would later murder the remaining Vietnamese in the country during their rule. Democratic Kampuchea and the Khmer Rouge The Khmer Rouge government adopted the mysterious term Angkar, or 'the organisation', and the identities of its leaders remained confidential until 1977. The official head of state was Khieu Samphan, but the two men in control of the party were Pol Pot and Ieng Sary. The ultimate objective of the Khmer Rouge was to erase the structure of the Cambodian state, which they viewed as feudal, capitalist, and serving the agendas of both the landholding elite and imperialists. In its place, they hoped to create a classless society based entirely on worker-peasants. The radical ideologies and goals of the Khmer Rouge were alien concepts to the masses. The socialist revolution held very little popular appeal, which led Pol Pot and his cadres to use ultra-nationalist sentiment, repressive and murderous rule, and propaganda aimed at demonising the Vietnamese to maintain control. Even before the Vietnam War ended, the relationship between the Khmer Rouge—which was in the process of seizing power from a US-backed government headed by Lon Nol—and North Vietnam was strained. Clashes between Vietnamese communists and Khmer Rouge forces