page_title: Cambodian–Vietnamese War
section_title: 1978: preparations for regime change
hierarchical_section_title: Cambodian–Vietnamese War / Diplomacy and military action / 1978: preparations for regime change
caption_attribution_description: Tiếng Việt: Hài cốt tại nhà mồ Ba Chúc, Tịnh Biên, An Giang. English: Skulls of females who have been massacred by the Khmer Rouge, Tịnh Biên county, An Giang Province.
context_page_description: The Cambodian–Vietnamese War, known in Vietnam as the Counter-offensive on the Southwestern border, and by Cambodian nationalists as the Vietnamese invasion of Cambodia, was an armed conflict between Democratic Kampuchea, controlled by the Khmer Rouge, and the Socialist Republic of Vietnam. The war began with repeated attacks by the Kampuchean Revolutionary Army on the southwestern border of Vietnam, particularly the Ba Chuc massacre which resulted in the deaths of over 3,000 Vietnamese civilians. On 25 December 1978, Vietnam launched a full-scale invasion of Kampuchea, and subsequently occupied the country and removed the government of the Communist Party of Kampuchea from power.
  During the Vietnam War, Vietnamese and Cambodian communists had formed an alliance to fight U.S.-backed regimes in their respective countries. Despite their open display of cooperation with the Vietnamese, the Khmer Rouge leadership feared that the Vietnamese communists were scheming to form an Indochinese federation with Vietnam as the dominant force in the region.
context_section_description: Instead of being sobered by the Vietnamese show of force, the Kampuchean government boasted that the Vietnamese withdrawal was a major victory for Democratic Kampuchea, comparing it to the "defeat of U.S. imperialism" on 17 April 1975. The Kampucheans went on further to proclaim that "our 6 January victory over the annexationist, Vietnamese aggressor enemy has given all of us greater confidence in the forces of our people and nation, in our Kampuchean Communist Party and our Kampuchean Revolutionary Army, and in our Party's line of people's war". The Kampuchean leadership claimed that one Kampuchean soldier was equal to 30 Vietnamese soldiers, so if Kampuchea could raise two million soldiers from a population of eight million, it could wipe out Vietnam's population of 50 million and still have six million people left. In reality, Kampuchean leaders simply ignored the condition of the population in their own country and Vietnam; the Vietnamese, though poor, were in good physical condition, while Kampuchea's population was physically and mentally exhausted from years of hard labour, starvation and disease.
  In addition to the disparity in population, there was also a great disparity between the fighting capabilities of the armed forces of the two countries. In 1977, Vietnam was estimated to have 615,000 soldiers and 900 tanks, supported by a 12,000-member air force with 300 combat aircraft, including one squadron of light bombers. In comparison, Kampuchea had an army of 70,000, only a few heavy tanks, 200 armoured vehicles and limited air capability. Despite facing such heavy odds, Kampuchea showed no signs of hesitation as its military continued to assault Vietnam's border regions. In January 1978, KRA forces still held portions of Vietnamese territory and began overrunning Vietnamese outposts in Hà Tiên Province. On 27 January 1978, Vietnam started calling on the KRA along the border regions to overthrow the Khmer Rouge regime.
  Against the backdrop of military clashes, between 9 January and 20 February 1978, Vietnamese Deputy Foreign Minister Phan Hien made several trips to Beijing to hold discussions with representatives of the Kampuchean government, which ultimately proved to be fruitless. On 18 January 1978, China attempted to mediate between Kampuchea and Vietnam when Vice Premier Deng Yingchao (widow of Zhou Enlai) travelled to Phnom Penh, where her effort was met with strong resistance by Kampuchean leaders. Meanwhile, Vietnamese government officials began conducting secret meetings with So Phim, the Khmer Rouge leader in Kampuchea's Eastern Military Zone, to plan a military uprising backed by Vietnam. During that same period, military setbacks experienced by the KRA in the Eastern Military Zone prompted Pol Pot to label the region as a "nest of traitors".
  In order to purge the Eastern Military Zone of those he perceived to have been contaminated by the Vietnamese, Pol Pot ordered military units from the Southwest Zone to move into eastern Kampuchea and eliminate the "hidden traitors". Unable to withstand an attack from the Kampuchea Government, So Phim committed suicide while his deputy Heng Samrin defected to Vietnam. On 12 April 1978, the Kampuchean government declared they and Vietnam could negotiate again if the Vietnamese gave up their expansionist ambitions and recognised Kampuchea's sovereignty. However, there was also a pre-condition requiring Vietnam to meet several obligations through a seven-month trial ceasefire. The Vietnamese government immediately rejected the demand. In response, two KRA divisions penetrated up to 2 km (1.2 mi) into Vietnamese territory and massacred over 3,000 Vietnamese civilians in the village of Ba Chúc in An Giang Province.
  In June 1978, the VPAF started bombing KRA positions along the border regions, flying about 30 bombing sorties per day and inflicting heavy casualties on the Kampucheans. By that stage in the conflict, most surviving leaders of the Eastern Military Zone had escaped into Vietnam, where they assembled at various secret camps with the purpose of forming a Vietn
caption: Skulls of victims of the Ba Chúc Massacre
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