taking power. The NDH leadership abolished racial laws and sent a request for collaboration with the Allies on 6 May, but all of these efforts failed. While the NDH leadership may have organized a civilian retreat to bolster their claims that the Yugoslav Communists were after innocent civilian victims, the sheer number of civilians slowed down the retreat, and made surrender to the Allies unfeasible. Some observers believed the government was using the civilians as a human shield against the Ustaše. The majority of the civilian refugees reportedly held anti-Communist views or feared reprisals. Divisions of three Yugoslav armies were pursuing the Axis forces. Some units of the Yugoslav 4th Army managed to reach Carinthia before or at the same time as the retreating columns. Additional divisions of the 3rd and 4th Armies were sent to the area in order to capture southern Carinthia and prevent the Axis retreat. The 1st and 2nd Armies were halted near Celje, while the 3rd Army advanced further in pursuit of the retreating columns. On 6 May 1945, the government of the NDH fled Zagreb and reached a site near Klagenfurt, Austria on 7 May. Pavelić and the military leadership left Zaprešić on the evening of 7 May, intending to join the rest of the NDH regime in Austria. The bulk of the NDH leadership, including Pavelić, escaped in early May, fleeing to Western Europe and Latin America. Partisans captured only a small number of senior military NDH officers. Zagreb was defended by parts of the 1st Division of the Army of NDH and the 41st and 181st German Divisions, deployed along the unfinished fortified "Zvonimir line" between Sveti Ivan Žabno and Ivanić-Grad. The fierce battle with the Yugoslav 1st Army lasted from 5–8 May. The single bloodiest day in the 1,240-day long history of the 1st Proletarian Brigade was 7 May, with 158 killed and 358 wounded in the fighting for Vrbovec. Besides the HOS, Slovene Home Guard and the German Army Group E, other military units were retreating. The remnants of the Serbian State Guard, two regiments of the Serbian Volunteer Corps, and a group of Chetniks surrendered to the British near the Italian-Yugoslav border on 5 May. These units were not repatriated to Yugoslavia. The Montenegrin National Army, formed in April 1945 by Sekula Drljević with the support of the NDH government, to gather Montenegrins from NDH in the unit, were