The colonial administration was thereby ended and French Indochina was dissolved under the Geneva Accords of 1954. Vietnam was further divided into North and South administrative regions at the Demilitarised Zone, roughly along the 17th parallel north, pending elections scheduled for July 1956. A 300-day period of free movement was permitted, during which almost a million northerners, mainly Catholics, moved south, fearing persecution by the communists. This migration was in large part aided by the United States military through Operation Passage to Freedom. The partition of Vietnam by the Geneva Accords was not intended to be permanent, and stipulated that Vietnam would be reunited after the elections. But in 1955, the southern State of Vietnam's prime minister, Ngô Đình Diệm, toppled Bảo Đại in a fraudulent referendum organised by his brother Ngô Đình Nhu, and proclaimed himself president of the Republic of Vietnam. At that point the internationally recognised State of Vietnam effectively ceased to exist and was replaced by the Republic of Vietnam in the south—supported by the United States, France, Laos, Republic of China and Thailand—and Hồ's Democratic Republic of Vietnam in the north, supported by the Soviet Union, Sweden, Khmer Rouge, and the People's Republic of China.