In the territory of Bosnia and Herzegovina, the cause of Serb rebellion was the Ustaše policy of deportations, forced conversions and mass killings of Serbs, as was the case elsewhere in the NDH. Resistance to Communist leadership of the anti-Ustasha rebellion among the Serbs from Bosnia also developed in the form of the Chetnik movement and autonomous bands which were under command of Dragoljub Mihailović. Whereas the Partisans under Serb leadership were open to members of various nationalities, those in the Chetniks were hostile to Muslims and exclusively Serbian. The uprising in Bosnia and Herzegovina started by Serbs in many places were acts of retaliation against the Muslims, with thousands of them killed. A rebellion began in June 1941 in Herzegovina. On 27 July 1941, a Partisan-led uprising began in the area of Drvar and Bosansko Grahovo. It was a coordinated effort from both sides of the Una River in the territory of southeastern Lika and southwestern Bosanska, and succeeded in transferring key NDH territory under rebel control.