The Belgian Congo became independent in June 1960. After a brief period of political unrest, Katanga Province seceded unilaterally from the Congo to form the State of Katanga under Moïse Tshombe. Fearing that the Congo's left-leaning political leaders, especially Patrice Lumumba, would nationalise its holdings, the UMHK supported Tshombe and became a major force within the new state. During the province's secession, the Union transferred 1.25 billion Belgian francs (35 million USD) into Tshombe's bank account, an advance on 1960 taxes which should in fact have been paid to Lumumba's government. In 1963, the secession was ended and Katanga reintegrated into the Congo.