In 1943 , the Germans suffered major losses on the Eastern Front and the Italians signed an armistice with the Allies , leaving behind significant armaments that the Partisans used against the occupiers and the UstaÅ e. Fighting continued for a short while after the formal surrender of German Army Group E on 9 May 1945 , and many refugees attempted to escape to Austria . In 1943 , the Germans suffered major losses on the Eastern Front and the Italians signed an armistice with the Allies , leaving behind significant armaments that the Partisans used against the occupiers and the UstaÅ e. Fighting continued for a short while after the formal surrender of German Army Group E on 9 May 1945 , as Axis forces and many refugees attempted to escape to Austria .