'Waldlauf' was a German and Croat operation against the partisan forces of Marshal Josip Broz Tito by Generalleutnant Johann Mickl’s 392nd Division (kroatische) in the Lika area of occupied Yugoslavia (1 April 1944).
After Generalleutnant Alexander Bouquin’s 114th Jägerdivision had been redeployed from Yugoslavia to Italy in January 1944, and with most of its surviving elements guarding the German lines of communications and the Adriatic coast, General Ernst von Leyser’s XV Gebirgskorps lacked the strength to launch the planned 'Morgenstern' to take the parts of the Lika region held by the partisan XI Corps. By the time the weather started to improve late in March 1944, the corps had drawn together a strength sufficient for offensive operations to reduce partisan-held areas, and the decision to launch 'Waldlauf' was further spurred by constant partisan attacks on the German positions in the Otočac area.
From 1 April the 392nd Division was to take control of the Gacka river valley from the partisan 35th 'Lika' Division, and thereby secure the German westward lines of communication in the area of Ogulin, Brinje and Senj, and also to establish an overland link with the garrison of Gospić. After this, it was planned, further operations would follow to take the Plitvice lakes area and the Krbava valley in order to link Generalleutnant Eduard Aldrian’s 373rd Division (kroatische) and the 392nd Division.
Despite its appreciation that there was more German traffic on the area’s roads, the staff of the 35th Division believed that this was nothing more than the movements of regular supply convoys, and therefore ordered an attack against the village of Prozor on the night of 30/31 March. Prozor was the most vulnerable southern German position near Otočac, itself partially blockaded by the partisans. Even information provided by the 3rd Brigade of the 13th Division from Staro Selo, which suggested an imminent German offensive, was ignored by both the 35th Division and the XI Corps, and the partisan forces were therefore caught in an offensive rather than defensive deployment.
The attack on Prozor came as surprise to Germans, whose first reaction was a belief that this was a pre-emptive attack against their own operation. The 4th Batterie of the 392nd Artillerieregiment, which just arrived in Prozor, came under heavy partisan attack but was relieved when the German advance moved out from Otočac at 02.00, forcing the partisans to break off their attack by 05.00 and retreat to their starting lines. As the German advance gathered pace and distance, the staff of the 35th Division lost contact with its 1st and 2nd Brigades. The Axis advance had three axes: from Otočac toward Gacko and Dabar in order to push the partisans toward the Plitvice lakes area using the 19th Ustase Battalion and 392nd Aufklärungsabteilung, from Stajnica using the 20th Ustase Battalion supported by parts of 847th Grenadierregiment and 392nd Artillerieregiment, and from Perusić toward Turjanski by the 32nd and 34th Ustase Battalions.
By the evening of 31 March the chaos of the local situation had persuaded the staff of 35th Division to order the withdrawal of most of rear area elements toward Korenica and the Plitvice lakes area. To aid the hard-pressed 35th Division, the 13th Division attacked along the road from Ogulin toward Brinje and Senj, and this compelled the 392nd Division to detach some units to protect this essential line of communication. This inevitably delayed operations against Plitivce and Krbava, and forced the 392nd Division to carry out 'Keulenschlag'.
The partisan casualties in 'Waldlauf' are thought to have been 51 men killed, 142 wounded and more than 100 missing. The operation was considerably more successful than the Germans had expected, but lack of strength prevented any immediate exploitation of the new tactical situation, and thus gave the partisans time to regroup and establish a new defensive line reinforced by the General Staff of Croatia and the 8th 'Kordun' Division.
The 392nd Division was severely overstretched, and was therefore forced to abandon to the partisans parts of the area it had just taken. There followed several smaller German operations to capture Vrhovine and the Plitvice lakes area.