After the successful German counter-insurgency operations Uzice and Mihailovic, and the split with the Partisans, Mihailović went on the run in early December 1941. Ostojić maintained a small headquarters consisting mainly of the intelligence staff, which remained close to Mihailović and his small personal staff as he moved around the Rudnik Mountain area during the rest of the winter, ending in February 1942. Mihailović eventually made his way to Montenegro, where he arrived in June 1942. Ostojić, Hudson and other officers joined him soon after, travelling through Italian-held towns by truck disguised as troops of the Nedić regime, a puppet government in the German-occupied territory of Serbia. By this time, the Chetnik movement had determined not to fight the Germans, and had commenced collaborating with the Nedić regime soon after they attacked the Partisans at Užice. By the time Mihailović reached Montenegro, an increasing proportion of Chetnik detachments throughout Yugoslavia were also collaborating with the Italians in Montenegro and the areas of the NDH they occupied.