ソン・サン
During this period, the Khmer Serei had been reduced to 'a collection of petty warlord movements' that operated along the Thai-Kampuchean frontier. At various intervals during the 1980s, these groups composed of Khmer Rouge and various pro-Sihanouk or pro-Son Sann factions conducted sporadic military activities against President Heng Samrin’s Vietnamese-sponsored People's Republic of Kampuchea (PRK). Son Sann was to use some of these former Khmer Serei supporters as the basis of the Khmer People's National Liberation Front movement, formed in 1979.