The Congo Crisis (5 July 1960-25 November 1965) was a period of political upheaval and conflict in what is now the Democratic Republic of the Congo that occurred in the aftermath of the Belgian withdrawal from the region. On 30 June 1960, Belgium granted independence to the Belgian Congo, but questions of federalism, ethnicity, and government remained unresolved, leading to an army mutiny breaking out in July and violence erupting between black and white civilians. Belgium sent troops to support the withdrawal of its civilians from the country, and Belgium also supported the secession of the gold-rich country of Katanga in the south, as well as the secession of neighboring South Kasai, from the central government of Congo-Leopoldville.
The United Nations sent peacekeepers to the Congo, but Secretary-General Dag Hammarskjold refused to support the central government against the separatist rebels, leading to Congolese Prime Minister Patrice Lumumba asking for the Soviet Union to send military advisers and other support; this created a deadlock between Lumumba and President Joseph Kasa-Vubu. The army commander Joseph-Desire Mobutu responded to Lumumba's alignment towards the Soviet Union with a military coup, and he expelled the Soviet advisers, created a new government under his control, and had Lumumba imprisoned and subsequently executed in 1961. Lumumba supporters under Antoine Gizenga founded a communist government at Congo-Stanleyville in the eastern parts of the country, and the republic was crushed in 1962, despite receiving support from the USSR.
After UN leader Hammarskjold's death in a 1961 plane crash, the UN took a more aggressive stance against the separatists, and UN troops assisted the Leopoldville government with crushing the Katanga and South Kasai secessionist movements by early 1963. The Katangese leader Moise Tshombe was recalled to lead an interim coalition government with Mobutu, but Maoist "Simbas" rose in rebellion in the east of the country, derailing peace negotiations. The Simbas proclaimed a "People's Republic" in Stanleyville, leading to the UN peacekeepers and the Congolese government pushing back. In November 1964, US and Belgian troops launched Operation Dragon Rouge to free hostages taken by the Simbas, and they rescued most of them, while 24 were killed. The Simbas were defeated soon after, and elections were held in March 1965. After Tshombe and Kasa-Vubu were unable to decide the new leader of the country, Mobutu led a November 1965 coup d'etat, transforming the Congo into a dictatorship that would be renamed "Zaire" in 1971 and would remain in existence until his 1997 deposition.