This was the German and Croat first stage of a major operation against the partisan forces of Marshal Josip Broz Tito in the area of Kordun, Banija, Popoku and Turpolje in German-occupied Yugoslavia (7/29 December 1943).
The entire undertaking was schemed in three phases with the object of destroying those partisan formations, totalling some 13,000 men, threatening the German lines of communication between the valley of the Sava river and the Adriatic sea, and was thus aimed at the Yugoslav IV Corps (7th and 8th Divisions, and 1st ‘Kordun’, ‘Banija’ and ‘Cazin’ Partisan Detachments), the 28th Division and the units of the Zumberak and Posavina sector (‘Joza Vlahovic’ Brigade, and ‘Zumberak-Pokupsko’ and ‘Turopolje-Posavina’ Partisan Detachments).
The entire German three-phase undertaking comprised the ‘Wolf’ (ii) five-day operation against Kordun by General Ernst von Leyser’s XV Gebirgskorps, the ‘Panther’ (viii) seven-day operation against Banija by the same corps, and the ‘Weihnachtsmann’ four-day operation against Pokuplje.
The Axis strength for the whole sequence was some 30,000 men based on the bulk of Generalleutnant Hermann Niehoff’s 371st Division (about 10,000 men), Generalleutnant Hellmuth von Pannwitz’s 1st Kosaken-Kavalleriedivision less its 2nd Kosaken-Reiterbrigade, four infantry battalions and one artillery battalion of Generalleutnant Emil Zellner’s 373rd Division (kroatisch) of about 2,500 men, and Croat home defence army units (about 1,500 men) comprising eight Ustaše companies and one home defence company of the Operations District Lika, and about 1,000 Moslem militiamen. These constituted the primary offensive force available to the Axis undertaking, and would move off from two starting lines, name that between Ogulin, Karlovac, Bosanska Krupa and Bosanski Novi, and that between Kostajnica, Sisak, Petrinja and Glina. The static formations to prevent the retreat of the Yugoslav IV Corps from Korduna in the west and from Banija in the east were the remaining 2,900 men of the 371st Division, the remaining 4,400 men of the Operations District Lika, 2,360 men of Generalleutnant Helmuth Huffmann’s 277th Division, and 1,465 men of SS-Standartenführer Johannes Mühlenkamp’s SS Gruppe ‘Mühlenkamp’ on the line linking Ogulin, Karlovac and Zagreb; and the remaining strength of the 1st Kosaken-Kavalleriedivision and 373rd Division (kroatisch), and 2,040 men of the 1st Jägerregiment holding line between Sisak, Sunja, Kostajnica and the lower part of the Una river.
The Germans began ‘Wolf’ (ii) on 7 December by advancing one reinforced regiment of the 371st Division from Karlovac along the axis from Vojnic via Vrginmost to Glina and another of the same division’s regiments along the axis from Ogulin across Ostarije and Slunj toward Velika Kladusa with goal of destroying the Yugoslav 8th Division after encircling it on the Banija; the Germans also desired to destroy the supply bases of the Yugoslav IV Corps in the same area. Simultaneously the 1st Kosaken-Kavalleriedivision and 373rd Division pinned down the Yugoslav 7th Division with attacks along the line between Glina, Sunja, Bosanski Novi and Bosanska Krupa. However, as a result of a German intelligence failure, the main part of the Yugoslav 8th Division was outside the encirclement attacks of the 371st Division, but in path of German advance on the first day was the ‘Kordun’ Partisan Detachment and parts of the of Yugoslav 8th Division’s 2nd Brigade.
On 9 December right-hand column of the 371st Division captured Slunj and Velika Kladusa, and left-hand column took Vojnic on 7 December and Vrginmost three days later. By now the German operation had apparently stalled, for the 371st Division ceased its clearance of the Petrova mountain area on 11 December, cancelled the planned clearance of the area between the Petrova mountain area and Samarica, and started to regroup in the area of Glina on 15 December instead on 11 December as planned.
On the night of 9/10 December the concentrations of the 1st Kosaken-Kavalleriedivision in the villages of Panjani, Majur and Stubljani were taken under attack by the 1st and 3rd Brigades of the Yugoslav 7th Division, and on 11 December the two brigades repeated the attacks and also started to attack the concentration in the village of Grabostani. At this stage ‘Wolf’ (ii) gave way to ‘Panther’ (viii), the second phase of the operation, which began on 12 December as the main part of the 1st Kosaken-Kavalleriedivision started to move forward from Petrinja, Kostajnica and Kozibroda, while the 373rd Division, parts of 2nd Jägerregiment and the Moslem militia pushed forward from the line between Bosanski Novi and Gvozdansko toward Samarica, from Otoka over Buzima to the north-east, and from Cazin toward Velika Kladusa. These movements were effected in co-operation with the 371st Division in an attempt to destroy the Yugoslav 7th Division and destroy its supply bases in Samarica.
The Germans admitted that the rate of their advance was significantly slower than planned as a result of the partisan destruction of bridges and obstruction of the lines of communications. Especially bitter fighting took place of the axes toward Bosanski Novi, Dvor na Uni and Beslinec. After a four-day delay, on 16 December the units of the 371st Division started to advance from the Glina area toward Zirovac and Samarica, and the Yugoslav 7th Division moved the main part of its strength to the west from Glina via Klasnic to Zirovac. On 17 December the Germans close their pincer movement round Samarica and began to clear the encircled area. On the same day they started, for completion on the following day, their complete withdrawal from Banija: the 373rd Division returned to its garrison area in valley of the Una river, and the 371st Division and 1st Kosaken-Kavalleriedivision to the area of Glina and Sisak.
These movements ended ‘Panther’ (viii) and marked the effective beginning of ‘Weihnachtsmann’.
Meanwhile the Yugoslav 8th Division was clearing the area between Velika Kladusa and Cazin of the smaller home defence garrisons and Moslem militia with one and then, from 22/23 December, three brigades and the ‘Cazin’ Partisan Detachment. Although the results were not very significant in terms of the numbers of Axis troops killed or captured, the partisan undertaking meant that region which two weeks earlier had been the staging area for the Axis offensive was now patrolled by a whole partisan division.
During the night of 18/19 December the ‘Turopolje-Posavina’ Partisan Detachment completed a notably successful attack on the garrison of the village of Sopnica, capturing most of the garrison and destroying a warehouse filled with aircraft bombs and ammunition for anti-aircraft guns. Operating with part of the Yugoslav 28th Division, elements of the same detachment carried out a successful attack on Kurilovec airfield near Zagreb. Over the same period and in response to orders from higher headquarters to ease the pressure on the Yugoslav IV Corps, units of Yugoslav 13th and 18th Divisions attacked the Ustaše in Vrbovsko on 15 December, leading to bitter fighting which lasted to 23 December and the Ustaše retreat to Ogulin.
‘Weihnachtsmann’ began as the third phase of the Axis operation on 26 December. A reinforced regiment of the 1st Kosaken-Kavalleriedivision began to move forward from the area of Sisak along the axis to the villages of Letovanic, Poljanek and Gajec. At the same time a reinforced regimental group of the 371st Division advanced along the axis from Glina to the villages of Stari Farkasic, Hotnja and Gladovec, while a second reinforced regimental group of the same division advance along the axis from Glina toward the villages of Pokupsko, Cerje and Gradac na Kupi. The object of these movements was to trap and destroy the Yugoslav 28th Division and the partisan units of the Žumberak-Pokupsko sector in the Turopolje and Posavina areas, where they posed a constant threat to the road and railway links from Zagreb to Karlovac and to Sisak, and also to the airfields in the area to the south of Zagreb. The undertaking was also designed to destroy the partisan forces’ equipment and ammunition dumps in the area between the Sava and Kupa rivers.
In parallel with these movements, part of the 371st Division and 1st Sector started to advance from Karlovac past the village of Donje Kupcine toward the village of Gradac to prevent the retreat to the south of partisan units in the area across the Kupa river. By now the partisans were approaching exhaustion in the face of considerably greater numbers, and in an effort to avoid encirclement the Yugoslav 28th Division crossed to the left bank of the Sava river during night of 28/29 December and retreated toward Moslavina. At the same time units of the Žumberak and Posavina sector move toward Žumberak. The German follow-on actions found nothing as they swept the country between Sava and Kupa, and were stopped on the evening of 29 December after the German command had learned of the retreat of partisans’ main force.
As usual in such operations, the heaviest price was paid by the civilian population, of which many were killed or wounded. At the same time the Axis forces seized or destroyed large quantities of stores and animal feed, and also took 4,500 head of the region’s larger livestock.