Rouge began trying to refashion all of Cambodia in the image of the poor peasantry, whose rural, isolated, and self-sufficient lives were regarded as worthy of emulation. As of May 1972, the group began ordering all of those living under its control to dress like poor peasants, with black clothes, red-and-white krama scarves, and sandals made from car tyres. These restrictions were initially imposed on the Cham ethnic group before being rolled out across other communities. Pol Pot also dressed in this fashion. CPK members were expected to attend regular (sometimes daily) "lifestyle meetings" in which they engaged in criticism and self-criticism. These cultivated an atmosphere of perpetual vigilance and suspicion within the movement. Pol Pot and Nuon Chea led such sessions at their headquarters, although they were exempt from criticism themselves. By early 1972, relations between the Khmer Rouge and its Vietnamese Marxist allies were becoming strained and some violent clashes had broken out. That year, the North Vietnamese and Viet Cong main-force divisions began pulling out of Cambodia, primarily because they were needed for the offensive against Saigon. As it became more dominant, the CPK imposed increasing numbers of controls over Vietnamese troops active in Cambodia. In 1972, Pol Pot suggested that Sihanouk leave Beijing and tour the areas of Cambodia under CPK control. When Sihanouk did so, he met with senior CPK figures, including Pol Pot, although the latter's identity was concealed from the king. Collectivisation and the conquest of Phnom Penh: 1973–1975 In May 1973, Pol Pot ordered the collectivisation of villages in the territory it controlled. This move was both ideological, in that it built a socialist society void of private property, and tactical, in that it allowed the Khmer Rouge greater control over the food supply, ensuring that farmers did not provision government forces. Many villagers resented the collectivisation and slaughtered their livestock to prevent it from becoming collective property. Over the following six months, about 60,000 Cambodians fled from areas under Khmer Rouge control. The Khmer Rouge introduced conscription to bolster its forces. Relations between the Khmer Rouge and the North Vietnamese remained strained. After the latter temporarily reduced the flow of arms to the Khmer Rouge, in July 1973 the CPK Central Committee agreed that the North Vietnamese should be considered "a friend with a conflict". Pol Pot ordered the internment of many of the Khmer Rouge who had spent time in