The 'Apatin-Kaposvár Offensive Operation' in the Hungarian/Yugoslav border area was the Soviet and Yugoslav undertaking known to the latter as the 'Batinska Operacija' (7 November/10 December 1944).

This was the fourth of the 10 sub-operations together constituting the 'Budapest Strategic Offensive Operation', whose other sub-operations were the 'Kecskemét-Budapest Offensive Operation' (29 October/10 December), the 'Szolnok-Budapest Offensive Operation' (29 October/10 December), the 'Nyíregyháza-Miskolc Offensive Operation' (1 November/10 December), the 'Esztergom-Komárno Offensive Operation' (20 December 1944/15 January 1945', the 'Szekesfehervar-Esztergom Offensive Operation' (20 December 1944/13 February 1945) and the 'Assault on Budapest Operation' (27 December 1944/13 February 1945).

The offensive was undertaken by Marshal Sovetskogo Soyuza Fyedor I. Tolbukhin’s 3^rd Ukrainian Front largely to support the 2^nd Ukrainian Front’s offensive farther to the north toward Budapest. The crossing of the Danube river and the seizure of bridgeheads at Batina and Apatin took place with the active participation of the Yugoslav 51^st Division of Major General Danilo Lekić-Spanac’s XII Corps of the People’s Liberation Army.

On 29 October, Marshal Sovetskogo Soyuza Rodion Ya. Malinovsky’s 2^nd Ukrainian Front launched the 'Budapest Strategic Offensive Operation'. Soviet forces broke through to Budapest’s outer defensive line, but initially failed to enter the city itself, which was held by German and Hungarian troops of Generaloberst Johannes Friessner’s Heeresgruppe 'Süd'. Each side deployed major reinforcements onto the approaches to the Hungarian capital, and the battle reached almost unprecedented intensity and ferocity. Both sides changed the direction of their attacks, launched counterattacks and major counter-offensives, but soon it became clear that the available Soviet forces could not take the Budapest defensive area.

In this regard, the 3^rd Ukrainian Front, which had been regrouped after the completion of the 'Belgrade Offensive Operation' in the north-eastern region of Yugoslavia, was ordered to pass its positions to the People’s Liberation Army of Yugoslavia, relocate to the southern part of Hungary, and occupy a defensive zone along the Danube river from its confluence with the Drava river to the city of Bahia. The 3^rd Ukrainian Front was to cross the Danube river and develop an offensive along its southern bank in order to break into the gap between the northern end of Lake Balaton and Budapest, encircling Budapest from the south-west; part of the front’s forces were also to bypass Lake Balaton from the south. The start date for the operation was set as 26 November.

The area was defended by Vezérezredes Jëno Major’s Hungarian 2^nd Army within Heeresgruppe 'Süd', but during the course of the operation, the whole area was transferred to the supervision of Generalfeldmarschall Maximilian Reichsfreiherr von Weichs’s Heeresgruppe 'F'.

At the start of the operation, the 3^rd Ukrainian Front had only General Leytenant Mikhail N. Sharokin’s 57^th Army, the much weakened XVIII Tank Corps and General Polkovnik Vladimir A. Sudets’s 17^th Air Army, from which a number of elements had been withdrawn. Since these forces were clearly inadequate for the front to fulfil its assigned tasks, General Leytenant Ivan V. Galanin’s 4^th Guards Army was transferred from the Stavka reserve, but as it was currently located in the south of Romania, it could not be delivered to its new position before the middle of November. The 3^rd Ukrainian Front’s total strength after this was 205,370 men.

Despite the fact that both armies were still in transit to the offensive’s launch area, the order to start the operation was not delayed, and on 7 November the 57^th Army went over to the offensive with the LXXV Corps, which had not yet completed its concentration. At this time the rest of the army was on the march. On the first day, the Soviet troops managed to capture one small bridgehead in the area to the north of the city of Apatin, and on the night of 9 November, to the north of the Croat village of Batina, a second bridgehead was seized. Fierce fighting erupted as the Soviets fought to enlarge their bridgeheads and unite them into a single lodgement. In these battles, the 3^rd Ukrainian Front’s troops were actively assisted by the Danube Naval Flotilla. On 13 November, another of the 57^th Army’s corps was brought into the battle in the Batina bridgehead, bit it was only on 23 November that the Batina and Apatin bridgeheads were united into single lodgement. The 57^th Army’s third corps and Galanin’s 4^th Guards Army were brought into this lodgement which, by the end of 26 November, had been enlarged to a width of 31 miles (50 km) and depth of between 8.7 and 10.6 miles (14 and 17 km). The city of Mohács was taken. Finally, the conditions had thus been created for a breakthrough the German and Hungarian defences.

On 27 November, the 3^rd Ukrainian Front launched a decisive offensive, which on its very first day broke through the defences of Hungarian troops exhausted in the previous fighting. The Hungarians' nicely organised defence system was shattered, and many of the army’s formations and units were isolated from each other and began an indiscriminate retreat. The pace of the Soviet offensive was now 12.5 to 18.5 miles (20 to 30 km) per day, and the 57^th Army took the large city of Pécs on 29 November (as the Soviet troops approached, there was an uprising of Hungarian miners) and Kaposvár on 2 December, and reached the southern tip of Lake Balaton. To stop the Soviet offensive at tis point, the Germans were compelled as a matter of urgency to bring up General Maximilian de Angelis’s 2^nd Panzerarmee. After an advance of more than 60 miles (100 km), formations and units of the 57^th Army reached the 'Margarethe-Linie' defensive line between Lake Balaton and the Drava river, where they went over to the defensive.

On the southern bank of the Drava river near the town of Barcs, which the Soviet forces had taken on 7 December, Soviet and Yugoslav troops created a large bridgehead, which posed a major threat to the rear of Heeresgruppe 'F'. In view of von Weichs’s lack of defensive success, the 2^nd Panzerarmee and the entire German defence zone in this sector were transferred back to Heeresgruppe 'Süd'.

The formations and units of Galanin’s (from 18 November General Georgi F. Zakharov’s) 4^th Guards Army also advanced to the north. On 30 November the army took the city of Szekszárd. To the north, the Germans committed a Panzergrenadier division, but this was quickly outflanked and forced into a hasty retreat. On 1 December, with the assistance of the 'Gerjen Landing Operation' by vessels of the Danube Military Flotilla, this village was taken, and on 4 December, after an advance of some 80 miles (130 km) in several days, the 4^th Guards Army reached the northern tip of Lake Balaton and the area between Lake Balaton and Lake Velencei. As a result of its heavy losses, the Hungarian 2^nd Army was now disbanded, and Vezérezredes Károlyi Beregfy’s Hungarian 3^rd Army, which was defending along the Danube river, absorbed the remnants of the disbanded army and was deployed against the 4^th Guards Army, which had been defeated it by the beginning of December. According to Friessner, two infantry divisions and one brigade of riverine marines were completely destroyed.

Only on the hastily prepared defensive line between Lake Balaton and Velencei did the German forces manage to slow the Soviet offensive. For this, Heeresgruppe 'Süd' had to transfer four German divisions, including Panzer formations, from Budapest to the area. As in both sectors the 3^rd Ukrainian Front had reached the German' well-sited defensive line, already occupied by German forces, the front’s breakthrough required the accumulation of stronger forces, a regrouping and the replenishment of ammunition, so on 10 December the front went over to the defensive and the 'Apatin-Kaposvár Offensive Operation' had been completed.

In the 'Apatin-Kaposvár Offensive Operation'. therefore, the 3^rd Ukrainian Front had pinned and weakened significant forces of the Hungarian 2^nd Army and, in the operation’s final stage, wholly defeated it. The safety of the 2^nd Ukrainian Front’s left wing as it advanced on Budapest had been ensured. Moreover, the 3^rd Ukrainian Front deeply outflanked the entirety of the Budapest defensive area from the south and thereby created the conditions for the Hungarian capital’s encirclement. The offensive had taken about 10 cities and more than 500 small settlements, as well as important industrial areas.

At the beginning of December 1944, the Soviet supreme command came to the conclusion that the forces of the 2^nd Ukrainian Front would not on their own be adequate to the task of defeating the German and Hungarian forces defending Budapest, which were being strengthened steadily. So it was decided to combine the efforts of both fronts in a single operation and to undertake a significant strengthening of the 3^rd Ukrainian Front at the expense of the 2^nd Ukrainian Front. After the regrouping and replenishment that followed, on 20 December both fronts again went onto the 'Esztergom-Komarno Offensive Operation' and 'Székesfehérvár-Esztergom Offensive Operation of their joint-enterprise 'Budapest Strategic Offensive Operation'.

During the 'Apatin-Kaposvár Offensive Operation', the 3^rd Ukrainian Front lost 6,790 men killed or missing and 25,460 men wounded or taken ill. The losses of the German and Hungarian forces during this operation are not known but, in light of the operation’s nature, they were probably similar to those of the Soviet forces.