The Vienna Offensive was launched by the Soviet 3rd Ukrainian Front in order to capture Vienna in Austria. The offensive lasted from 2 to 13 April 1945. The city of Vienna was surrounded and under siege for most of the offensive until its capture.
Joseph Stalin reached an agreement with the Western Allies prior to April 1945 concerning the relative postwar political influence of each party in much of Eastern and Central Europe; however, these agreements said virtually nothing about the fate of Austria, then officially considered to be merely the Ostmark area of Greater Germany after the Anschluss. As a result, the victory of a Soviet offensive toward Austria and the liberation by the Red Army of a large part of this country would have been very beneficial for subsequent postwar negotiations with the Western Allies.
After the failure of Operation Spring Awakening (Unternehmen Frühlingserwachen), Sepp Dietrich's 6th SS Panzer Army retreated in stages to the Vienna area. The Germans desperately prepared defensive positions in an attempt to guard the city against the rapidly arriving Soviets.
On 30 March, the advancing Soviets crossed the Hron and Nitra Rivers, and after they took Sopron and Nagykanizsa crossed the border between Hungary and Austria. Tolbukhin was now ready to advance into Austria and take Vienna.
On 2 April, Vienna Radio denied that the Austrian capital had been declared an open city. On the same day, Soviet troops approached Vienna from the south after they overran Wiener Neustadt, Eisenstadt, Neunkirchen and Gloggnitz. Baden and Bratislava were overrun on 4 April.
After arriving in the Vienna area, the armies of the Soviet 3rd Ukrainian Front surrounded, besieged, and attacked the city. Involved in this action were the Soviet 4th Guards Army, the Soviet 6th Guards Tank Army, the Soviet 9th Guards Army, and the Soviet 46th Army. The "O-5 Resistance Group," Austrians led by Carl Szokoll wanting to spare Vienna destruction, actively attempted to sabotage the German defenses and to aid the entry of the Red Army.
The only major German force facing the Soviet attackers was the German II SS Panzer Corps of the 6th SS Panzer Army, along with ad hoc forces made up of garrison and anti-aircraft units. Declared a defensive region, Vienna's defense was commanded by General Rudolf von Bünau, with the II SS Panzer Corps units under the command of SS General Wilhelm Bittrich.
The battle for the Austrian capital was characterized in some cases by fierce urban combat, but there were also parts of the city the Soviets advanced into with little opposition. Defending in the Prater Park was the 6th Panzer Division, along the south side of the city were the 2nd and 3rd SS Panzer Divisions, and in the north was the Führer-Grenadier Division. The Soviets assaulted Vienna's eastern and southern suburbs with the 4th Guards Army and part of the 9th Guards Army. The German defenders kept the Soviets out of the city’s southern suburbs until 7 April. However, after successfully achieving several footholds in the southern suburbs, the Soviets then moved into the western suburbs of the city on 8 April with the 6th Guards Tank Army and the bulk of the 9th Guards Army. The western suburbs were especially important to the Soviets because they included Vienna's main railway station. The Soviet success in the western suburbs was followed quickly by infiltration of the eastern and northern suburbs later the same day. North of the Danube River, the 46th Army pushed westward through Vienna's northern suburbs. Central Vienna was now cut off from the rest of Austria.
By the 9th of April, the Soviet troops began to infiltrate the center of the city, but the street fighting continued for several days more. On the night of 11 April, the 4th Guards Army stormed the Danube canals, with the 20th Guards Rifle Corps and 1st Mechanized Corps moving on the Reichsbrücke Bridge. In a coup de main on 13 April, the Danube Flotilla landed troops of the 80th Guards Rifle Division and 7th Guards Airborne Division on both sides of the bridge, cutting demolition cables and securing the bridge. However, other important bridges were destroyed. Vienna finally fell when the last defenders in the city surrendered on the same day. Bittrich's II SS Panzer Corps, however, pulled out to the west on the evening of 13 April to avoid encirclement. The same day, the 46th Army took Essling and the Danube Flotilla landed naval infantry up the river by Klosterneuburg.
While the street fighting was still intensifying in the southern and western suburbs of Vienna on 8 April, other troops of the 3rd Ukrainian Front by-passed Vienna altogether and advanced on Linz and Graz.
On the 10th, all but two of the bridges in the city had been destroyed. The Floridsdorf bridge had been left intact by a Fuehrer Order dictating that the bridge be held at all costs. The 2nd SS Panzer, "Das Reich" left a dozen artillery pieces including 37mm anti-aircraft guns to hold off enemy attacks. That night, the "Das Reich", including their last remaining three dozen armored vehicles, pulled out of the city for the last time. Vienna had fallen, and the Germans now moved northwest to hold a next defensive line.
By 15 April, armies of the Soviet 3rd Ukrainian Front pushed even further into Austria. The completely exhausted remnants of what had been the 6th SS Panzer Army were forced to flee to the area between Vienna and Linz. Just behind the retreating Germans were elements of the Soviet 9th Guards Army and the Soviet 46th Army. The 26th Army and 27th Armies advanced towards the area north of Graz just behind the retreating 6th Army. The 57th Army and the Bulgarian 1st Army advanced towards the area south of Graz (near Maribor) just behind the retreating 2nd Panzer Army. None of these German armies was in any shape to do more than temporarily stall the advancing Soviet forces.
Some of Vienna's finest buildings lay in ruins after the battle. There was no water, electricity, or gas — and bands of people, both foreigners and Austrians, plundered and assaulted the helpless residents in the absence of a police force. While the Soviet assault forces generally behaved well, the second wave of Soviet troops to arrive in the city were badly disciplined, looting and raping in a several-week orgy of violence that has been compared to the worst aspects of the Thirty Years War.
Like Bittrich, General von Bünau left Vienna before it fell to avoid capture by the Soviets. From 16 April until the war's end, he led Generalkommando von Bünau, surrendering to the Americans on VE Day. von Bünau was held as a POW until April 1947. Bittrich also surrendered to U.S. forces and was held as a prisoner by the Allies until 1954. Fyodor Tolbukhin went on to command the Soviet Southern Group of Forces and the Transcaucasian Military District prior to his untimely death in 1949, reportedly from heart problems.
Austrian politician Karl Renner astutely set up a Provisional Government in Vienna sometime in April with the tacit approval of the victorious Soviet forces, and declared Austria's secession from the Third Reich.
Final orders of battle (after the Vienna Offensive)
German and German allied forces
On 30 April, the following order of battle was recorded by the German Army High Command (Oberkommando der Wehrmacht, or OKW). From 20 April-2 May, OKW moved from Zossen (near Berlin) to Mürwik (part of Flensburg in north Germany, near Denmark). This order of battle shows what remained "on paper" of the German armies that fought in Hungary and Austria.
- German 6th SS Panzer Army – east of Linz
- German 6th Army – north of Graz
- German 2nd Panzer Army – south of Graz (near Maribor)
Soviet and Soviet allied forces
The order of battle for the 3rd Ukrainian Front during the same period was:
- 4th Guards Army
- 20th Guards Rifle Corps
- 21st Guards Rifle Corps
- 41st Guards Rifle Division
- 62nd Guards Rifle Division
- 66th Guards Rifle Division
- 69th Guards Rifle Division
- 31st Guards Rifle Corps
- 6th Guards Tank Army
- 9th Guards Army
- 37th Guards Rifle Corps
- 38th Guards Rifle Corps
- 39th Guards Rifle Corps
- 26th Army
- 30th Rifle Corps
- 36th Guards Rifle Division
- 68th Guards Rifle Division
- 21st Rifle Division
- 104th Rifle Corps
- 74th Rifle Division
- 93rd Rifle Division
- 151st Rifle Division
- 135th Rifle Corps
- 233rd Rifle Division
- 236th Rifle Division
- 30th Rifle Corps
- 27th Army
- 57th Army
- 17th Air Army
- 5th Guards Cavalry Corps
- 1st Guards Mechanized Corps
- 18th Tank Corps
- 2nd Breakthrough Artillery Corps
- 9th Breakthrough Artillery Division
- 19th Breakthrough Artillery Division
- 7th Breakthrough Artillery Division
- 3rd Anti-aircraft Artillery Division
- 4th Anti-aircraft Artillery Division
- 9th Anti-aircraft Artillery Division
- 22nd Anti-aircraft Artillery Division
- 1st Bulgarian Army
- III Corps
- 10th Infantry Division
- 12th Infantry Division
- 16th Infantry Division
- IV Corps
- 3rd Infantry Division
- 8th Infantry Division
- 11th Infantry Division
- 6th Infantry Division
- III Corps
- Battle of Berlin
- Bombing of Vienna in World War II
- Eastern Front (World War II)
- History of Germany during World War II
- Battle of Budapest – 1944/45
- Operation Frühlingserwachen – 1945
- Battle of the Transdanubian Hills – 1945
- Nagykanizsa–Körmend Offensive – 1945
- Prague Offensive – 1945
- Soviet 3rd Ukrainian Front
- German 6th SS Panzer Army
- End of World War II in Europe
- Siege of Vienna (1529)
- Battle of Vienna (1683)
- Site soldat.ru lists casualties of 139,815 for the 3rd Ukrainian Front and 9,805 for the 1st Bulgarian Army for the period 16 March to 15 April 1945, but this total includes other operations in Hungary and Czechoslovakia as well as including a longer period of time than the Vienna battle lasted.
- Former members of O-5 tell a different story, claiming the bridge guards were actually O-5 members who turned their machine-guns on the Germans when they attempted to destroy the bridge. Toland 1965, p. 354.
- Descriptions of Soviet actions are from Ustinov 1982, pp. 238–239.
- Jukes 2002, p. 68.
- Berzhkov 1987, Chapter 5, Section 2.
- Dollinger & Jacobsen 1968, p. 199.
- Laffin 1995, p. 449.
- Dollinger & Jacobsen 1968, p. 182.
- Gosztony 1978, p. 261.
- Gosztony 1978, p. 262.
- Reynolds, Michael (2009). Sons of the Reich: II SS Panzer Corps. Barnsley: Pen & Sword Military. ISBN 978-184884-000-3.
- Gosztony 1978, p. 263.
- Johnson 1989, pp. 135–136.
- Dollinger & Jacobsen 1968, p. 177.
- Berzhkov, Velentin Mikhailovic (1987). Страницы дипломатической истории [The History of Diplomacy]. Moskva: Международные отношения.
- Laffin, John (1995). Brassey's Dictionary of Battles. New York: Barnes and Noble. ISBN 0-7607-0767-7.
- Dollinger, Hans; Jacobsen, Hans Adolf (1968). The Decline and Fall of Nazi Germany and Imperial Japan. New York: Crown.
- Gosztony, Peter (1978). Endkampf an der Donau 1944/45 (in German). Wien: Molden Taschenbuch Verlag. ISBN 3-217-05126-2.
- Johnson, Lonnie (1989). Introducing Austria. Riverside: Ariadne Press. ISBN 978-0-929497-03-7.
- Jukes, Geoffrey (2002). The Second World War (5): The Eastern Front 1941–1945. Osprey Publishing. ISBN 1-84176-391-8.
- Ustinov, D. F. (1982). Geschichte des Zweiten Welt Krieges (in German). 10. Berlin: Militärverlag der DDR.
- Toland, John (1965). The Last 100 Days. New York: Random House.
- Glantz, David (11 October 2001). "The Soviet‐German War 1941–45: Myths and Realities: A Survey Essay" (PDF). Clemson University.