In early 1964, the Simba Rebellion ("Simba Revolution") occurred, mushrooming into outright rebellion by May and June. By August rebels had overrun Stanleyville from their bases in Wanie Rukula. They closed the airport and barred civilians from leaving, including at least one foreign consular staff. A number of American and European nationals taken captive, and following intense negotiations Operation Dragon Rouge was launched by Belgium, the Armée Nationale Congolaise (ANC), and a plethora of foreign mercenaries under Colonel Mike Hoare to free the hostages.