In late 1944, with the German withdrawal from the Balkans and the advance of the Red Army and the Partisans, the situation for the Chetniks in Serbia and Montenegro became increasingly difficult. Mihailović, who favoured continued cooperation with the Germans to obtain weapons and ammunition, ordered all Chetnik forces, including those under Đurišić's command in Montenegro, to head towards Bosnia. While the Chetniks assisted the Germans in keeping control of the communication lines, Mihailović at the same time tried to win back the support of the Western Allies. The Germans withdrew from Montenegro in early December 1944, together with Đurišić's troops. The Montenegrin Chetniks were at this point reorganized into three divisions, and included the Sandžak Chetniks of Vuk Kalaitović. They numbered 8,700 men and were accompanied by around 3,000 civilians, mostly family members. After a 35-day march, suffering from cold, hunger and diseases, Đurišić's army reached the Trebava mountain in northeast Bosnia in mid-February 1945. Upon joining the rest of the Chetniks, Đurišić criticized Mihailović's leadership and advocated a retreat to Slovenia, where they would join other Chetnik units and await the arrival of Western Allies, as opposed to Mihailović's insistence on returning to Serbia. He decided to split from Mihailović and move toward the Slovene Littoral. Đurišić was joined by Dragiša Vasić, one of the chief Chetnik ideologues and Mihailović's political adviser, the detachments of Petar Baćović, leader of the Herzegovina Chetniks, and of Zaharije Ostojić, leader of the Eastern Bosnian Chetniks. Just before his departure, on 18 March, Đurišić was joined by a part of the Chetniks from Serbia.