 In early 1964 , a new crisis broke out as Congolese rebels calling themselves " Simba " ( Swahili for " Lion " ) rebelled against the government . They were led by Pierre Mulele , Gaston Soumialot and Christophe Gbenye who were former members of Gizenga 's Parti Solidaire Africain ( PSA ) . The rebellion affected Kivu and Eastern ( Orientale ) provinces . By August they had captured Stanleyville and set up a rebel government there . As the rebel movement spread , discipline became more difficult to maintain , and acts of violence and terror increased . Thousands of Congolese were executed , including government officials , political leaders of opposition parties , provincial and local police , school teachers , and others believed to have been Westernized . Many of the executions were carried out with extreme cruelty , in front of a monument to Lumumba in Stanleyville . Tshombe decided to use foreign mercenaries as well as the ANC to suppress the rebellion . Mike Hoare was employed to create the English @-@ speaking 5 Commando ANC at Kamina , with the assistance of a Belgian officer , Colonel Frederic Vanderwalle , while 6 Commando ANC was French @-@ speaking and originally under the command of a Belgian Army colonel , Lamouline . By August 1964 , the mercenaries , with the assistance of other ANC troops , were making headway against the Simba rebellion . Fearing defeat , the rebels started taking hostages of the local white population in areas under their control . These hostages were rescued in Belgian airdrops ( Dragon Rouge and Dragon Noir ) over Stanleyville and Paulis with U.S. airlift support . The operation coincided with the arrival of mercenary units ( seemingly including the hurriedly formed 5th Mechanised Brigade ) at Stanleyville which was quickly captured . It took until the end of the year to completely put down the remaining areas of rebellion . 
