After Germany declared war on Portugal in March 1916 the Portuguese government sent more reinforcements to Mozambique (the South Africans had captured German South West Africa in 1915). These troops supported British, South African and Belgian military operations against German colonial forces in German East Africa. In December 1917, German colonial forces led by Colonel Paul von Lettow-Vorbeck invaded Mozambique from German East Africa. Portuguese, British and Belgian forces spent all of 1918 chasing Lettow-Vorbeck and his men across Mozambique, German East Africa and Northern Rhodesia. Portugal sent a total of 40,000 reinforcements to Angola and Mozambique during World War I.