The Belgian Congo was directly involved in the two world wars. During World War I, an initial stand-off between the Force Publique and the German colonial army in German East Africa (Tanganyika) turned into open warfare with a joint Anglo-Belgian invasion of German colonial territory in 1916 and 1917 during the East African campaign. By 1916 the Belgian commander of the "Force Publique", Lieutenant-General Charles Tombeur, had assembled an army of 15,000 men supported by local bearers – Reybrouck indicated that during the war no less than 260,000 native bearers were called upon – and advanced to Kigali. Kigali was taken by 6 May 1916, and the army went on to take Tabora on 19 September after heavy fighting. In 1917, after Mahenge had been conquered, the army of the Belgian Congo, by now 25,000 men, controlled one-third of German East Africa.