The French were not in a strong position to immediately reassert their authority in their former colony, French Indochina, after the Japanese invaders withdrew at the end of World War II. In the north, the Vietminh, a political party led by Ho Chi Minh (1890?-1969), proclaimed the independent Democratic Republic of Vietnam. France agreed to recognize Vietnam as a free state within the French Union, but negotiations dragged on. In December 1946, Vietminh forces attacked French garrisons, and during the ensuing years guerrilla activity increased in the countryside. In 1949, a Vietnamese provisional government, headed by Emperor Bao Dai (1913-97), was established, which was recognized by France and, in 1950, by the United States. The communist-dominated Vietminh rejected any remnant of French authority and consequently attacked French outposts along Vietnam's border with China, from whom they received substantial military aid. In 1951, the Vietminh created a common front with communist groups in Laos and Cambodia (Kampuchea) and became more and more aggressive. They were led by General Vo Nguyen Giap (1912-), who launched an attack on March 13, 1954, against the strategic French stronghold at Dienbienphu in northwestern Vietnam. Giap's siege lasted 56 days; his Vietminh troops continually attacked with artillery and mortar fire until the French defenders, short of ammunition, surrendered on May 7, 1954. Meanwhile, an international conference in Geneva was working out an agreement whereby the fighting would cease and the French would withdraw. The Vietminh set up a government north of the 17th parallel, while the Vietnamese non-communists set upa government south of the demarcation line. The was was unpopular in France, most of whose citizens were relieved when it was over, despite the defeat and the loss of influence in Southeast Asia. In July 1954, Vietnam was divided into the Democratic Republic of Vietnam (North Vietnam) and the Republic of Vietnam (South Vietnam).