A force of Germans and Askaris under Paul Emil von Lettow-Vorbeck had recently won a costly victory against the British at the Battle of Mahiwa, in present-day Tanzania and ran very short of food and other supplies.

Portugal was part of the Entente and a belligerent, employing troops in France and Africa; so a force under Major João Teixeira Pinto was sent to stop von Lettow-Vorbeck from crossing the border.

The capitulation of the Portuguese enabled the Germans to seize a large quantity of supplies and continue operations in East Africa until the end of the war.

With only antiquated weapons and no means of resupply, von Lettow-Vorbeck decided to invade Portuguese East Africa in hopes of acquiring sufficient supplies to continue the war.

The Portuguese force was a native contingent led by European officers under João Teixeira Pinto, a veteran with experience fighting in Africa.

Taking heavy casualties, having lost their commanding officer, and finding themselves hopelessly outnumbered, the Portuguese finally surrendered despite the fact that they had enough military supplies to continue the action.

The Portuguese, on the other hand, had suffered a massive defeat and by failing to prevent von Lettow-Vorbeck's force from crossing the Rovuma allowed him to continue his campaign until the end of the war.

Von Lettow-Vorbeck abandoned and destroyed the majority of his force's German weaponry for which he had no ammunition and armed his troops with Portuguese and British weapons.