This organisation provided a much-needed rallying point for Cambodian leftists opposed to Khmer Rouge rule, channelling efforts towards positive action instead of empty denunciations of the genocidal regime. The KUFNS provided as well a framework of legitimacy for the ensuing invasion of Democratic Kampuchea by Vietnam and the subsequent establishment of a pro-Hanoi regime in Phnom Penh. Vietnamese policymakers finally opted for a military solution and, on 22 December 1978, Vietnam launched its offensive with the intent of overthrowing Democratic Kampuchea. An invasion force of 120,000, consisting of combined armour and infantry units with strong artillery support, drove west into the level countryside of Cambodia's southeastern provinces. After a seventeen-day blitzkrieg, Phnom Penh fell to the advancing Vietnamese on 7 January 1979. The retreating Armed Forces of Democratic Kampuchea (RAK) and Khmer Rouge cadres burned rice granaries, which, along with other causes, provoked a severe famine all over Cambodia beginning in the last half of 1979 and which lasted until mid-1980. On 1 January 1979, the Salvation Front's central committee proclaimed a set of "immediate policies" to be applied in the areas liberated from the Khmer Rouge. First the communal kitchens were abolished and some Buddhist monks would be brought to every community to reassure the people. Another of these policies was to establish "people's self-management committees" in all localities. These committees would form the basic administrative structure for the Kampuchean People's Revolutionary Council (KPRC), decreed on 8 January 1979, as the central administrative body for the PRK. The KPRC served as the ruling body of the Heng Samrin regime until 27 June 1981, when a new Constitution required that it be replaced by a newly elected Council of Ministers. Pen Sovann became the new prime minister. He was assisted by three deputy prime ministers – Hun Sen, Chan Sy, and Chea Soth. On 10 January 1979, the DK army had been routed and the Vietnamese troops had captured the capital Phnom Penh. The KPRC proclaimed that the new official name of Cambodia was the People's Republic of Kampuchea (PRK). The new administration was a pro-Soviet government supported by a substantial Vietnamese military force and civilian advisory effort. Despite the Vietnam-sponsored invasion and control, and the loss of independence that went along with it, the new order was welcomed by almost the entire Cambodian population due to the Khmer Rouge brutality.