The fifth front was the area of
Kordun and
Banovina. That territory was part of medieval Croatian-Slavonian kingdom, but during the Turkish wars it became deserted. To the deserted areas settled Serbs and Vlachs, who in that area were - along with Croats living there - soldiers of the Austrian Military Frontier. In this area the war was as savage as elsewhere, with the difference that all smaller urban centers were occupied as well. The Serb-Yugoslav Army penetrated as deeply into North as Karlovac and Sisak, but those (larger) cities managed to defend themselves.
This area too was liberated during the
Operation Storm.
From TV Belgrade: the reporter speaks about the "brave" acts of Serb-Yugoslav soldiers in that area (subtitles in Serbian only, but pictures as well say much)
Serbian soldiers deliberately shooting a church