Phnom Malai is a mountain area in Malai District, Banteay Meanchey Province of Cambodia. The district became a Khmer Rouge stronghold and battleground through the 1980s and 1990s. Today it is a remote and sparsely populated border area with scattered settlements mostly made up of former rebels.
Refugees from refugee camps in Aranyaprathet, Thailand, were forcefully sent back across the border in 1980 to areas under Khmer Rouge control and many of them ended up in Phnom Malai. The process was organized by pro-Democratic Kampuchea cadres, but it was presented to the press as "voluntary". It was supported by the United States government, who took a dim view of the existing pro-Vietnamese Cambodian regime, as well as countries like Malaysia, Thailand and Singapore, whose representative exhorted the disoriented refugees to "go back and fight."
By 1981 Phnom Malai was not self-sufficient, the Khmer Rouge uniforms and weapons came from China, channeled through the Thai military, and the food from markets across the border in Thailand. In this period, the Khmer Rouge was able to rebuild its military, now titled the "National Army of Democratic Kampuchea" (NADK), as well as its infamous ruling party, the Communist Party of Kampuchea (CPK), the sinister and shadowy "angkar", as the Party of Democratic Kampuchea. By mid-1980s, with the cooperation of the West and China, the Khmer Rouge had grown to about 35 to 50 thousand troops and committed cadres.
Pol Pot lived in the Phnom Malai area, giving interviews in the early 1980s accusing all those who opposed him of being traitors and "puppets" of the Vietnamese until he disappeared from public view. In 1985, his "retirement" was announced, but he kept hiding somewhere close by, still pulling the Khmer Rouge strings of power.