The Khmer Rouge troops capture Phnom Penh and government forces surrender. The war between government troops and the communist insurgents had been raging since March 1970, when Lt. Gen. Lon Nol had ousted Prince Norodom Sihanouk in a bloodless coup and proclaimed the establishment of the Khmer Republic.
Between 1970 and 1975, Lon Nol and his army, the Forces Armees Nationale Khmer (FANK), with U.S. support and military aid, battled the communist Khmer Rouge for control of Cambodia. During the five years of bitter fighting, approximately 10 percent of Cambodia's 7 million people died. When the U.S. forces departed South Vietnam in 1973, both the Cambodians and South Vietnamese found themselves fighting the communists alone. Without U.S. support, Lon Nol's forces fought on, but eventually succumbed to the Khmer Rouge. With the surrender, the victorious Khmer Rouge evacuated Phnom Penh and set about reordering Cambodian society. This resulted in a killing spree and the notorious "killing fields." Eventually, hundreds of thousands of Cambodians were murdered or died from exhaustion, hunger, and disease.