 On 6 April 1941 , when the World War II German @-@ led Axis invasion of Yugoslavia began , Morava was based at Stara <unk> on the Tisza river , as the flagship of the 2nd Mine Barrage Division . This force was responsible for the Hungarian border , and came under the operational control of the 7th Infantry Division Potiska . The remainder of the 2nd Mine Barrage Division consisted of the river tug R @-@ XXI , the river transport Senta , and a few mobilised customs motorboats , based further south on the Tisza at Senta . On 7 April , Morava withdrew to Senta , where she was attacked by German aircraft . According to her commander , Poručnik bojnog broda Božidar <unk> , her crew shot down one German aircraft and captured a Luftwaffe Oberstleutnant . On 10 April , Morava was ordered to withdraw to conform with the retreat of the 2nd Army Group of the Royal Yugoslav Army from Bačka and Baranja . On the evening of 11 April , Morava anchored at the confluence of the Danube and Sava near Belgrade , along with her fellow monitors Vardar and Sava , and <unk> took command of the flotilla . The three captains conferred , and decided to scuttle their vessels due to the high water levels in the rivers and low bridges , which meant insufficient clearance for the monitors to navigate freely . The crews of the monitors were transshipped to two tugboats , but when one of the tugboats was passing under a railway bridge , demolition charges on the bridge exploded prematurely and the bridge fell onto the tugboat . Of the 110 officers and men aboard the vessel , 95 were killed . 
