'Nibelungenfahrt' was a German and Croat operation against the partisan forces of Marshal Josip Broz Tito in the Krbavsko plain area of the puppet state of Croatia in German-occupied Yugoslavia (13/23 January 1944).
The operation’s objective was the destruction of the partisan supply base in the Krbavsko plain within the area bordered by Otočac, Bihać and Gospić. The partisan forces were the 1st, 2nd and 3rd Brigades of the 13th Division under the command of the Operational Headquarters for Lika. This headquarters controlled the 1st Brigade of some 1,070 men, the 2nd Brigade which was the former 4th Brigade of the 13th Division, and one artillery battalion. The 13th Division controlled the 3rd Brigade in the area of Brlog, Zuta Lokva and Vratnik to slow the German advance and block its progress toward Brinje and Krivi Put, and the 1st Brigade in the area of Krivi Put and Novi Vinodolski with the same task as the 3rd Brigade. Under the direct command of the General Staff of Croatia, the 13th Division’s 2nd Brigade was located in the village of Glavace, to the north-west of Otočac, to block any advance towards Dabar.
The German forces, supported by a modest number of Croat troops of the Group 'Zapoli' (Zapanda Lika, or western Lika), were provided by Generalleutnant Alexander Bouquin’s 114th Jägerdivision. It had been planned on 2 January 1944 that the 114th Jägerdivision would be transferred to Istria as replacement for Generalleutnant Wilhelm Raapke’s 71st Division, which had its headquarters in Opatija and its main units deployed in Rijeka, Trieste and Postojna. The 114th Jägerdivision was to move by road via Obrovac, Sinj, Drnis, Knin, Lapac, Bihać and Slunj and then board trains from Karlovac and Zagreb. Then on 8 January it was decided to have the division march directly to Istria to clear the partisans (13th Division and Operational Headquarters for Lika) in Lika and along the Croat coast.
General Ernst von Leyser’s XV Gebirgskorps desired to use the division for a secondary operation, namely a sweep of Krbava, but this was denied by Generaloberst Dr Lothar Rendulic’s 2nd Panzerarmee.
The division’s advance in 'Nibelungenfahrt' started on 13 January with attack on the partisan 2nd Brigade in the area round Budak. In order to secure right flank of their advance toward Perusić, the Germans lost a whole day in an effort to push two battalions of the 1st Brigade, supported by an artillery battalion of the Operational Headquarters for Lika, out of Siroka Kula. The Germans finally managed to drive the partisans from Siroka Kula to Ljubovo, which was taken on 15 January after an Ustase column had advanced into Vrebac and Barlete, thereby exposing the 1st Brigade’s left flank. The focus of the German advance was now switched back to the area held by the 2nd Brigade, and the Germans took Perusić on 16 January. For next two days the Germans moved slowly north over mountainous terrain. Knowing that once they had taken the Lesće pass the Germans would swiftly push motorised units into the Gacka river valley, the Operational Headquarters for Lika suggested the evacuation of Otočac, where the General Staff of Croatia and other partisan institutions and rear area units were based. The Germans took Lesće at about 12.00 on 18 January, and arrived in Otočac during the evening of the same day. A partisan artillery battalion was moved from Ljubovo across Korenica and Vrhovina to Zaluznica, from which it could fire on the German columns in the Otočac area.
On 19 January the 114th Jägerdivision's reconnaissance battalion overcame the resistance of the 3rd Brigade in the area of Brlog and Zuta Lovka, and then advanced over the Vratnik pass to seize control of Senj on Adriatic coast. As the 114th Jägerdivision continued its advance, the 1st Brigade launched attacks which, the brigade reported, destroyed one truck, killed 50 horses and captured 10 rifles together with 15,000 rounds of ammunition.
By 23 January most of the 114th Jägerdivision had been moved to Italy in order to help in checking the Allied 'Shingle' beach-head at Anzio, only one group of regimental size remaining to support 'Dreznica', which had been launched on the same day by Generalleutnant Johann Mickl’s 392nd Division (kroatische) with an advance from from Ogulin toward Jasenak, Dreznica, Jezerane and Brinje.
The attempt by the remnant of the 114th Jägerdivision to advance from Zute Lovke toward Brinje on 23 January was halted by the 3rd Brigade, and the remnant finally linked with the 392nd Division (kroatische) near Dreznica on 25 January.
'Nibelungenfahrt' ended on 30 January, the Germans admitting the loss of only six men killed and 53 wounded in exchange for 79 partisans killed and 48 captured, and up to this time the operation had tied down most of partisan 13th Division, leaving only the 1st Detachment and elements of the 8th 'Kordun' Division to oppose the 392nd Division (kroatische).
As indicated above, the start of 'Shingle' on 22 January resulted in the transfer of the 114th Jägerdivision to Generalfeldmarschall Albert Kesselring’s Heeresgruppe 'C' in Italy, and led to the abandonment of Otočac to the partisans and the postponement of further operations against the partisan movement until more troops could be deployed into the theatre. This gave the partisans in Lika and Gorski Kotar a measure of respite during which they reorganised their forces into the XI Corps with the 13th and 35th Divisions. Moreover, the German failure to secure Krbava also left the partisans with a strong logistical base and improvised airfield through which the Allies could deliver supplies from Italy and evacuate badly wounded partisans.