 Complete the following phrase:  Following the outbreak of World War I and the German invasion of Belgium, Tombeur became the commander of the Belgian colonial forces on the border with German East Africa. He presided over the re-organisation of the Force Publique and, in April 1916, led a Belgian force into Rwanda as part of the British-led East African Campaign. By June 1916, the whole of Rwanda had fallen and Burundi was occupied soon afterwards. Tombeur was made military governor of the Belgian Occupied East African Territories consisting of the future Belgian mandate of Ruanda-Urundi. The expeditionary force soon headed for the German military stronghold at Tabora in modern-day Tanzania. After 