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 Westernised. 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 at Kamina, with the assistance of a Belgian officer, Colonel Frederic Vanderwalle, while 6 Commando (Congo) 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 (Operations Dragon Rouge and Dragon Noir) over Stanleyville and Paulis airlifted by U.S. aircraft. 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.