On the Soviet side, the troops of the 3rd Ukrainian Front under Marshal Fyodor Tolbuchin with a partial contingent of the 2nd Ukrainian Front under Marshal Rodion Malinowski and other troops joined the “Vienna Operation”. about 640,000 soldiers and officers the Red Army counted in this mission – with over 12,000 guns, 1,300 tanks and armored vehicles, and around 1,000 aircraft. Another 100,000 men were from Bulgaria.
In contrast, on the German side there were Army Groups South, E and F with Hungarian troops – a total of 410,000 soldiers and officers, around 700 tanks and howitzers, 6,000 artillery pieces, and around 700 aircraft.
The Wehrmacht associations were set up in three sections. A strip five to seven kilometers wide ran along the Gran: trenches with firing positions, secured by minefields. The access roads to the city of Stuhlweißenburg were also mined. The second section ran 20 to 30 kilometers away. The entrances to the Raab were fortified, the city of the same name was shielded as a stronghold – the Germans were certain that it could not be taken away. The third section ran along the Austro-Hungarian border. Here too: armored trenches, barriers and minefields. Several small towns were developed into fortresses.
It started at 3.35 p.m. on March 16. After an hour of artillery bombardment, two armies from the right flank of the 3rd Ukrainian Front went on the offensive. Before nightfall, the troops managed to wedge themselves up to seven kilometers into the defense of the Wehrmacht. The Germans put up violent resistance, fought particularly bitterly for Stuhlweißenburg.
The Soviet troops pursued the Wehrmacht units, which gave up ground to retreat to the third fortification section: On April 4, the forces of the 2nd Ukrainian Front liberated the city of Bratislava and took up positions in front of Vienna. The Germans were encircled from three sides.
The fighting was district by district. The only option for the Wehrmacht to withdraw was the Reichsbrücke – the only bridge that the Germans had not blown up. After all, they also mined these; and only with the courageous intervention of a Soviet airborne division could the explosion be prevented. At noon on April 13, Vienna was free from the Wehrmacht.