From the start of the war, the Chetniks expelled Muslims and Croats from areas they controlled, and engaged in mass killings. In late 1941, they connected with various independent pro-Chetnik groups that participated in revolts against the Ustaše-led Independent State of Croatia (NDH). With fascist Italy's help, the Chetniks established a form of civil and military government in large parts of eastern Bosnia, which was followed by discriminatory measures and systematic massacres of non-Serbs in the region. The Chetnik genocidal campaign reached a peak between October 1942 and February 1943. Military defeats and the loss of Allied support compelled the Chetniks to moderate their policy towards Croats and Muslims. Despite these efforts, massacres of civilians continued until the end of the war. The terror tactics against the Croats were, to at least an extent, a reaction to the terror carried out by the Ustaše, however the largest Chetnik massacres took place in eastern Bosnia where they preceded any significant Ustaše operations. Croats and Bosniaks living in areas intended to be part of Greater Serbia were to be cleansed of non-Serbs regardless, in accordance with Mihailović's directive of 20 December 1941.