This was a German and Croat operation against the partisan forces of Josip Broz Tito in the Bilo mountain region of the puppet state of Croatia in Axis-occupied Yugoslavia (19/22 February 1943).
The undertaking’s objective was the destruction of a partisan concentration of the 4th 'Slavonia' Division in the mountain area to the south-west of Virovitica.
The German contribution to the operation took the form of elements of Generalleutnant Josef Brauner von Haydringen’s 187th Reserve-Division, and that of the Croats the 2nd Battalion and 4th Battalion of Pukovnik Josip Solc’s (soon Pukovnik Stjepan Peričić's) 1st Mountain Brigade, 1st Battalion and 4th Battalion of Pukovnik Stjepan Grlić's 4th Mountain Brigade and the Personnel Replacement Transfer Company/1st Regiment.
The Axis forces swept the area and made contact with the partisan forces, but the latter’s main force escaped. According to the Germans, the Axis losses were 11 men killed, 18 wounded and 34 missing, and those of the partisans 76 men killed, three wounded and five captured.