Zagreb, was appointed as his first officer. Drava was based at Bezdan when the German-led Axis invasion of Yugoslavia commenced on 6 April 1941, serving as the flagship of the 1st Mine Barrage Division. She was responsible for the Hungarian border on the Danube, under the operational control of the 30th Infantry Division Osiječka, which was part of the 2nd Army. At the time, the Yugoslav river flotilla consisted of four early twentieth-century river monitors which Yugoslavia had received from Austria-Hungary following World War I – Sava, Morava, Vardar and Drava. The river flotilla's commander, Edgar Angeli, was an Axis spy. He was later appointed as the commander of the Navy of the Independent State of Croatia. After the invasion began, Drava steamed upstream to Mohács in Hungary to shell the airfield there on 6 and 8 April, but was subjected to daily attacks by the Luftwaffe. On 10 April, Drava and Morava were ordered to sail downstream to conform with the withdrawals of the 1st and 2nd Army's from Bačka and Baranja. Around 2:00 p.m. the following day, a Yugoslav lookout near Batina signaled Drava that four Hungarian patrol boats, armed with guns, were coming down the Danube from the direction of Mohács. Drava engaged the patrol boats at a range of , and drove the small Hungarian flotilla north again. At 4:00 p.m., Berić once again ordered the shelling of the airfield at Mohács. Morale on the ship was good, but when Berić met with Royal Yugoslav Army elements later that day, he became aware of the situation elsewhere, and nine crew members deserted. Around 3:00 a.m. on the morning of 12 April, Drava encountered the ruined railway bridge at Bogojevo, which prevented it from navigating further along the Danube, and anchored nearby. By 5:00 a.m., the obstruction had been cleared, and Drava continued sailing. While Drava had been anchored, seven crew members deserted their posts, commandeered the ship's motorboat and headed for Erdut. At 7:30 a.m., Drava came under attack from nine Luftwaffe Junkers Ju 87 Stuka dive bombers of Sturzkampfgeschwader 77 flying from Arad, Romania. According to the historian Velimir Terzić and the naval author Zvonimir Freivogel, Dravas anti-aircraft gunners managed to shoot down three of the incoming aircraft, but the aviation authors Christopher F. Shores, Brian Cull and Nicola Malizia state that the gunners "claimed" they had shot down three. The monitor's anti-aircraft gunners were