World War I broke out in 1914. German colonies were originally meant to preserve their neutrality as mandated in the Berlin Convention, but fighting soon broke out on the frontier between German East Africa and the Belgian Congo around Lakes Kivu and Tanganyika. As part of the Allied East African Campaign, Ruanda and Urundi were invaded by a Belgian force in 1916. The German forces in the region were small and hugely outnumbered. Ruanda was occupied over April–May and Urundi in June 1916. By September, a large portion of German East Africa was under Belgian occupation reaching as far south as Kigoma and Karema and as far eastwards as Tabora in modern-day Tanzania. In Ruanda and Urundi, the Belgians were welcomed by some civilians, who were opposed to the autocratic behaviour of the kings. The territory captured was administered by a Belgian military occupation authority ("Belgian Occupied East African Territories") pending an ultimate decision about its political future. An administration, headed by a Royal Commissioner, was established in February 1917 at the same time as Belgian forces were ordered to withdraw from the Tabora region by the British.