This was a Yugoslav series of attacks by the forces of Marshal Josip Broz Tito on Croat and German garrisons in the Podravina area of the puppet state of Croatia within German-occupied Yugoslavia (25 September/16 October 1944).
The 'Ratweek' (i) air offensive was followed by a general offensive ordered by Tito, and at the same time the Soviet advance through Romania forced the Germans and the Croats to redeploy their units, in particular Generalleutnant Helmut von Pannwitz’s 1st Kosaken-Kavalleriedivision, which was moved from the Podravina area to hold the the primary railway line linking Zagreb, Dugo Selo and Novska, and also that linking Zagreb and Varazdin, both of which were targets for major partisan sabotage activity. Several garrisons were also withdrawn and towns were abandoned to the partisans, among these being Daruvar on 14 September, Hercegovac and Garesnica.
This left Podravina relatively lightly garrisoned and therefore exposed to attack by the partisan VI and X Corps. Another factor in this situation was the amnesty offered by Tito on 30 August, which promised that there would be no retribution for any member of an Axis formation who joined the partisan movement by 15 September, but also that those who remained loyal to the Axis would be treated as traitors. This had major impact on the already demoralised Croat home defence army, which was now still further beset by defections not only of individual men but also of entire units; other units merely disintegrated as their men went home. The Croat strength was further diminished by the fact that the Germans also disarmed units they considered unreliable. The VI Corps alone reported the arrival of 5,567 Croat soldiers to join the partisan ranks.
So far as offensive operations were concerned, the partisan forces made attacks on Podravska Slatina, Čađavica, Virovitica, Pitomača, Klostar, Đurđevac, Vitje, Podravski Novigrad, and Koprivnica. Although this last attack failed, most of the Podravina area was now under partisan control, so increasing the size of the previously held area of the Daruvar and Pozega basins. After the 'Batinska Operacija' and the Soviet advance into Hungary, an overland connection was established with liberated parts of Yugoslavia, forcing the Germans to undertake an operation to crush what become known as the Virovitica bridgehead, which threatened the rear of the German formations on the Syrmian front.