The 'Assault on Budapest Offensive' was the Soviet and Romanian 50-day encirclement and capture of Budapest, the capital of Hungary (24 December 1944/13 February 1945).

An element of the larger 'Budapest Strategic Offensive Operation', the siege began when Budapest, defended by Hungarian and German troops, was first encircled on 26 December 1944 Soviet and Romanian forces. During the siege, about 38,000 civilians died through starvation or military action before city unconditionally surrendered on 13 February 1945.

After suffering almost 200,000 deaths in three years of fighting in the USSR, and with the front line approaching its own cities, by a time early in 1944 Hungary was ready to exit World War II. As political forces within Hungary pushed for an end to the fighting, Germany launched its 'Margarethe' pre-emptive undertaking on 19 March 1944 and its forces entered Hungary.

In October 1944, after the Western Allies' victories in Normandy and at Falaise, and after the collapse of the Eastern Front following the stunning success of the Soviet 'Bagration' summer offensive, Vezérfökapitány Miklós Horthy de Nagybánya, the Regent of Hungary, again attempted to negotiate a separate peace with the Allies. Upon hearing of Horthy’s efforts, Adolf Hitler launched 'Panzerfaust' to keep Hungary on the Axis side, and forced Horthy to abdicate. Horthy’s government was replaced by that of the 'Hungarist' Ferenc Szálasi, head of the far-right National Socialist Arrow Cross Party. As the new right-wing government and its German allies prepared to hold Budapest, SS-Gruppenführer und Generalleutnant der Waffen-SS Karl-Gustav Sauberzeig’s (from 7 December SS-Obergruppenführer und General der Waffen-SS Karl von Pfeffer-Wildenbruch’s) IX Waffen Gebirgskorps der SS (kroatisches) (two Waffen-SS divisions) was sent to strengthen the garrison of Budapest.

The besieging Soviet forces were part of Marshal Sovetskogo Soyuza Rodion Ya. Malinovsky’s 2^nd Ukrainian Front, and the formations of this front which took part in the fighting were General Polkovnik Ivan M. Managarov’s 53^rd Army and General Polkovnik Mikhail S. Shumilov’s 7^th Guards Army. Elements of Marshal Sovetskogo Soyuza Fyedor I. Tolbukhin’s 3^rd Ukrainian Front, including General Leytenant Ivan T. Shlemin (from January 1945 General Major Mikhail S. Filippovsky’s) 46^th Army, and General de divizie Nicolae Şova’s Romanian VII Corps were also involved.

Arrayed against the Soviet and Romanian forces was a collection of German army and Waffen-SS formations and Hungarian army forces.

The Soviet forces began their offensive against the city on 29 October 1944 as more than 1,000,000 men, divided into a pair of operational manoeuvre groups, advanced with the object of isolating Budapest from the rest of the German and Hungarian forces. On 7 November, Soviet and Romanian troops entered the Hungarian capital’s eastern suburbs, some 12.5 miles (20 km) from the old town. After a much-needed pause, the Soviets resumed their offensive on 19 December. On 26 December, the main road linking Budapest and Vienna was seized, and the Soviet forces thereby completing the encirclement of the city. The Nazi-supported Nemzetvezető (the self-styled Leader of the Nation), Szálasi, had already fled the city on 9 December.

As a result of the linking of the Soviets' two operational manoeuvre groups to the west of the city, nearly 33,000 German and 37,000 Hungarian troops, as well as over 800,000 civilians, became trapped within the city. Refusing to authorise any withdrawal, Hitler had declared Budapest to be a Festung (fortress) that was to be defended to the last man. Pfeffer-Wildenbruch was appointed as the commander of the city’s defences.

Budapest was a major target for Iosif Stalin, the Soviet leader, as the 'Argonaut' inter-Allied conference in Yalta was approaching and Stalin wished to display the USSR’s full military might to Prime Minister Winston Churchill and President Franklin D. Roosevelt. Stalin therefore instructed Malinovsky to seize the city without delay.

During the night of 28 December 1944, political crews of the 2^nd Ukrainian Front and 3^rd Ukrainian Front urged the besieged Germans, by radio and loudspeaker, to tell them of a negotiation for the city’s surrender. The Soviets offered humane surrender conditions and promised not to mistreat German and Hungarian prisoners. They also promised that the emissaries' groups would not be armed, and would arrive in cars marked by the flying of white flags. On the following day, two groups of Soviet emissaries appeared. The first, from the 3^rd Ukrainian Front, arrived at 10.00 in the Budafok sector and was taken to Pfeffer-Wildenbruch’s headquarters. Its attempt to negotiating came to nothing, however, as Pfeffer-Wildenbruch refused the surrender conditions and sent back the Soviet team. While the emissaries were en route to their lines, the Germans suddenly opened fire, killing one of the Soviets but not the other two men, who fell into a trench. The weight of the German fire was so heavy that the Soviets were not able to retrieve the body of their dead officer until the night of 29 December.

The second group of emissaries was sent by the 2^nd Ukrainian Front and arrived at 11.00 in the Kispest sector. When the emissaries arrived, the German garrison fired at them. The Soviet group’s leader appealed for a negotiation, but to no avail and was killed, together with his two subordinates, when German fire struck their car.

The Soviet offensive began in Budapest’s eastern suburbs and advanced through Pest, exploiting the large central avenues to speed their progress. Overwhelmed, the German and Hungarian forces attempted to trade space for time as a means of slowing the Soviet advance, but ultimately withdrew in order to shorten their defensive line and hoping to be able to use the hilly nature of Buda to their advantage.

In January, the Germans launched a three-part counter-offensive. This 'Konrad' was a joint German and Hungarian attempt to break through to the garrison encircled in Budapest. 'Konrad I' was launched on 1 January as SS-Obergruppenführer und General der Waffen-SS Herbert Otto Gille’s IV SS Panzerkorps attacked from Tata through hilly terrain to the north-west of Budapest in an effort to break the siege. On 3 January, the Soviets despatched four more divisions to meet the threat, and 'Konrad I' was brought to a halt near Bicske, less than 12.5 miles (20 km) to the west of Budapest, and the German force was compelled to withdraw on 12 January. The Germans then launched 'Konrad II' on 7 January, when the IV SS Panzerkorps attacked from the area of Esztergom toward Budapest’s airport, whose seizure would have improved the Germans' ability to supply the city by air, but the offensive was halted near the airport.

Street fighting within Budapest increased steadily in its intensity, and supply became a decisive factor with the loss of Ferihegy airport on 27 December, just before the start of the siege. Until 9 January, German troops were able to use some of the main avenues as well as the park next to Buda Castle as landing zones for aircraft and gliders despite the fact that these areas were under constant Soviet artillery fire. Before the Danube river froze, some supplies could also be sent by barge under the cover of darkness and fog. Food shortages rapidly became increasingly common, and the defenders had to rely on finding their own food sources, including their horses. The very low temperature of the time also had an adverse effect on the German and Hungarian troops. Soviet troops quickly found themselves in the reverse of the situation which had for a time benefitted the Germans in Stalingrad: they were able to take advantage of the urban terrain to place great reliance on the use snipers and combat engineers to advance.

Fighting broke out in the sewers, as each side used these for the movement of troops. Six Soviets even managed to reach Castle Hill and capture a German officer before returning to their own lines in a wholly underground undertaking. Such feats were rare, however, as the German and Hungarian forces used local residents to guide them into ambush positions. In the middle of January, the Soviet took Csepel island in the Danube river, together with this large island’s military factories that were still manufacturing Panzerfaust anti-tank weapons and artillery ammunition despite being under Soviet fire. In Pest, however, the situation of the Axis forces deteriorated and its garrison now faced the threat of being sundered in two by the Soviet advance. On 17 January, Hitler agreed to the withdrawal of the troops remaining in Pest to strengthen the defence of Buda. All five bridges spanning the Danube river became clogged with traffic as troops and civilians were evacuated, and German engineers destroyed all five of the bridges on 18 January despite protests by the Hungarians.

On 17 January, the IV SS Panzerkorps, which was be redeployed to an area to the north-east of Lake Balaton, completed its movement and on the following day attacked once again in 'Konrad III'. In two days the German armour reached the Danube river at Dunapentele, to the south of Budapest, and in the process ripping apart the Soviet front on the western side of the Danube river. By 26 January the German offensive had reached a point some 15.5 miles (25 km) from the Soviet perimeter round Budapest. Stalin ordered his forces to hold their ground at all costs, and two corps that has been despatched to assault Budapest were hastily redeployed to the south to counter the German offensive. The German forces which had reached a point only 12.5 miles (20 km) from the city were unable to maintain their impetus as a result of battle fatigue and supply problems. Budapest’s defenders asked permission to leave the city and escape the encirclement, but Hitler refused to consider any such thing.

The German forces could no longer hold their ground, however, and on 28 January were therefore compelled to withdraw and thus abandon much of the territory, with the notable exception of Székesfehérvár,they had occupied. This sealed the fate of the Budapest’s defenders.

Unlike Pest, which is built on flat terrain, Buda is built on hills. This allowed the defenders to site artillery and fortifications above the attackers, greatly slowing the Soviet advance. Gellért hill, the main citadel, was held by Waffen-SS units, which repelled several Soviet assaults. Nearby, Soviet and German forces fought for the city’s cemetery amid graves blasted open by artillery fire, and this phase of the Soviet assault lasted for several days.

The fighting on Margaret island, in the middle of the Danube river, was especially bloody. The island was still connected to the rest of the city by the remaining half of the Margaret bridge and was used by the Germans as a parachute drop zone as to provide cover for the improvised airstrips sited in the city centre. The Soviet formation involved in the fighting for the island was t5^th Guards Division.

On 11 February, Gellért hill finally fell to the Soviets after six weeks of fighting after the Soviets launched simultaneous heavy attacks from three directions. Soviet artillery resited to the could then dominate the entire city and shell all the remaining Axis defenders, who were concentrated in only a small area and suffering from malnutrition and disease. Despite their lack of supplies, however, the Axis troops refused to surrender and defended every street and house. By this time, some Hungarian soldiers who had defected changed sides and now fought on the Soviet side. After capturing the southern railway station in the course of a two-day bloodbath, Soviet troops advanced to Castle hill and on 10 February established a lodgement on the hill while almost cutting the remaining garrison in half.

Hitler still forbade Pfeffer-Wildenbruch authorisation either to abandon Budapest or to attempt a break-out. But the flights of DFS 230 small gliders bringing in supplies had ended a few days earlier and parachute drops had also been discontinued. In desperation, Pfeffer-Wildenbruch decided to lead the remnants of his force out of Budapest. Somewhat typically, the German commander did not either consult or inform the Hungarian commander of the city. However, Pfeffer-Wildenbruch now uncharacteristically included Vezérezredes Iván Kishindi Hindy, commander of the Hungarian I Corps, in this last desperate break-out attempt. On the night of 11 February, some 28,000 German and Hungarian troops began to make their way to the north-west away from Castle hill in three waves, each accompanied by thousands of civilians. Whole families, pushing prams and small hand carts, struggled through the snow and ice. However, Soviet forces were awaiting the attempted exodus in prepared positions around the Széll Kálmán tér area. The troops and civilians exploited the presence of heavy fog, and their first surprised the waiting Soviet soldiers and artillery, and by weight of numbers broke through and made it possible for many to escape. The second and third waves were altogether less fortunate: Soviet artillery and rocket batteries bracketed the escape area and deluged the area with fire that killed many thousands. Even so, between 5,000 and 10,000 people managed to reach the wooded hills to the north-west of Budapest and escape in the direction of Vienna, but only some 600 to 700 German and Hungarian soldiers reached the main German lines. The majority of the escapees were thus killed, wounded or taken prisoner by the Soviets. Pfeffer-Wildenbruch and Hindy were captured by Soviet troops as they emerged from a tunnel from the Castle district.

The last of Budapest’s defenders surrendered 13 February. The German and Hungarian military losses had been very high, and several divisions had been destroyed. The Germans lost all or most of the 13^th Panzerdivision, Panzerdivision 'Feldherrnhalle', 8^th SS Kavalleriedivision 'Florian Geyer' and 22^nd SS Freiwilligen Kavalleriedivision 'Maria Theresa'. The Hungarian I Corps was virtually annihilated, as well as the 10^th Division, 12^th Division ands 1^st Armoured Division.

The Soviet forces suffered between 100,000 and 160,000 casualties. The Soviets claimed that they had trapped 180,000 German and Hungarian troops in the Budapest pocket, and that they had captured 110,000 of these soldiers. However, immediately after the siege, the Soviets rounded up thousands of Hungarian civilians and added them to the prisoner count, so allowing the Soviets to validate their previously inflated figures.

Budapest itself lay in ruins, with more than four-fifths of its buildings destroyed or damaged, historic buildings such as the Hungarian parliament building and the castle among them. All seven bridges spanning the Danube river had been destroyed.

In January, some 32,000 ethnic Germans living in Hungary were arrested and transported to the USSR as forced labourers. In some villages, the entire adult population was taken to labour camps in the Donets river basin, where many died a result of hardship and ill-treatment. In overall terms, more than 500,000 Hungarians were transported to the USSR, this figure including between 100,000 and 170,000 ethnic Germans.

With the exception of 'Frühlingserwachen', which was launched in March, the siege of Budapest was for the Germans their last major operation on the southern front. The 'Assault on Budapest Operation' further depleted German strength, especially in Waffen-SS formations and units. For the Soviets, the siege of Budapest was a final rehearsal before the Battle of Berlin, and also paved their way to the 'Vienna Strategic Offensive Operation', which took Vienna on 13 April, exactly two months after the surrender of Budapest.

After Budapest’s surrender, the Soviet occupation forces forcibly conscripted all able-bodied Hungarian men and youths to build pontoon bridges across the Danube river. For weeks afterward, especially after the spring thaw, bloated bodies floated down the river and piled up against these same pontoons and bridge pylons.