Although the boundaries between the different factions were somewhat confused, the Khmer Rumdo are generally identified as those elements which were nominally loyal to Prince Sihanouk, but which were also leftist and supported by North Vietnam.

The 'Centre', led by Saloth Sar, Son Sen and Ieng Sary, had a strongly nationalistic ideology, and did not cooperate so much with North Vietnam, receiving most of its support from China; it also disliked Sihanouk, regarding him as a 'feudal' figure.

During the early part of the Civil War, the Khmer Rumdo were estimated to be by far the stronger element of the Cambodian forces opposing Lon Nol.

There is also evidence that there was a greater degree of religious and economic freedom permitted in the eastern areas, even after the fall of the Lon Nol regime in 1975.

Chakrey was executed in Tuol Sleng Detention Centre in 1976, the first high-ranking official to be sent there; while So Phim, the Eastern Zone Secretary, committed suicide.