Battle of Ngomano The Battle of Ngomano was fought between the German Empire and Portugal during the East African Campaign of World War I . A force of Germans and Askaris under Paul Emil von Lettow - Vorbeck had just won a costly victory against the British at the Battle of Mahiwa and were running critically low on supplies . To remedy the problem the Germans invaded Portuguese East Africa in an attempt to escape superior British forces to the north and resupply from captured Portuguese materiel . A Portuguese force under the command of Major João Teixeira Pinto was sent to stop von Lettow - Vorbeck from crossing the border , but was flanked by the Germans while encamped at Ngomano on 25 November 1917 . The resulting battle saw the Portuguese force nearly destroyed , with large numbers of troops killed and captured . The capitulation of the Portuguese force enabled the Germans to seize a large quantity of supplies , thereby allowing von Lettow - Vorbeck to continue his operations in East Africa until the end of the war . Background . By late November 1917 , the Germans in East Africa were left with few options if they wanted to continue the war . They were outnumbered drastically and were split up into several different columns . The two largest of these , under Theodor Tafel and Paul Erich von Lettow - Vorbeck , were completely cut off from each other . Although von Lettow - Vorbeck ' s column had defeated a large British force at the Battle of Mahiwa he had lost a large number of troops and expended virtually his entire supply of modern ammunition . With only antiquated weapons and no way of resupplying , the Germans were forced to invade Portuguese East Africa in order to maintain their effectiveness as a fighting force and continue the war . Although Tafel ' s force was intercepted by the Allies and capitulate d before reaching the border , von Lettow - Vorbeck and his column was able to reach the Rovuma River . Facing supply shortages , the German general then reduced his force by dismissing a large number of Askaris which could not be adequately equipped as well as a number of camp follower s . With his reduced force , von Lettow - Vorbeck made plans to attack the Portuguese garrison across the river at Ngomano . The Portuguese force was a native contingent led by European officers under João Teixeira Pinto , a veteran with experience fighting in Africa . Rather than prepare defensive positions , the Portuguese had begun building a large encampment upon their arrival at Ngomano on 20 November . Pinto had at his disposal 900 troops with six machine gun s and a large supply cache , but his inexperienced force was no match for von Lettow - Vorbeck ' s force , which crossed the river with between 1500 and 2000 hardened veterans as well as a large number of porters . Battle . At 07 : 00 on the morning of 25 November , the Portuguese garrison at Ngomano received word from a British intelligence officer that an attack was about to commence . Nevertheless , when the attack came they were unprepared . In order to distract Pinto and his men , the Germans shelled the camp from across the river with high explosive rounds . While the artillery attacked the camp , the Germans moved their forces upstream and crossed the Rovuma safely out sight of Pinto and his men . The Portuguese did not resist von Lettow - Vorbeck ' s forces when they crossed the river and remained encamped at Ngomago . The Germans were easily able to flank the Portuguese positions and completely envelop them with six companies of German infantry attacking the camp from the south , southeast , and west . Having been forewarned about the attack , the Portuguese commander had been able to begin preparations for the assault ; however , he had planned on receiving a frontal assault and when the force came under attack from the rear he was completely surprised . The Portuguese attempted to entrench themselves in rifle pits , but they became disoriented after Pinto and several other officers were slain early on in the engagement . The Germans had very little in the way of heavy weapons , as they had discarded most of their artillery and machine guns due to lack of ammunition . Despite the chronic ammunition shortage von Lettow - Vorbeck was able to move four machine guns up close to the rifle pits , using them only at close range to ensure his ammunition would not be wasted . The inexperience of the Portuguese proved to be their downfall , as despite firing over 30 , 000 rounds German casualties were extremely light , suffering only one casualty among their officers . Taking heavy casualties , having lost their commanding officer , and finding themselves hopelessly outnumbered , the Portuguese finally surrendered despite the fact that they had enough supplies to continue the action for quite some time further . Aftermath . The German casualties were light , with only a few Askaris and one European killed . 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 . Estimates of Portuguese casualties vary , with some sources providing figures of over 200 Portuguese killed and wounded and nearly 700 taken prisoner ; however , others state around 25 Portuguese killed along with 162 Askari , with almost 500 captured . The prisoners of war were used by the Germans as porters for the 250 , 000 rounds of ammunition , six machine guns and several hundred rifles that were also captured . With this equipment , the Germans managed to completely resupply their force . 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 the newly acquired Portuguese and British materiel . Portuguese uniforms seized from the captured prisoners were utilized to replace the ragged old German ones that the force had previously worn . Von Lettow - Vorbeck did not stay at Ngomano for long and soon marched his force south to attack more Portuguese positions , leaving only one company at Ngomano as a rearguard in case the British decided to follow him into Portuguese East Africa . His force won several more victories while seizing even more supplies and ammunition before moving back into German East Africa in 1918 .