 Complete the following phrase:  The Chetniks were active in the uprising in the German-occupied territory of Serbia from July to December 1941. As a result of the Battle of Loznica at the end of August, Mihailovićs Chetniks were the first to liberate a European city from Axis control. Following the initial success of the uprising, the German occupiers enacted Adolf Hitlers formula for suppressing anti-Nazi resistance in Eastern Europe, a ratio of 100 hostages executed for every German soldier killed and 50 hostages executed for every soldier wounded. In October 1941, German soldiers and Serbian collaborators perpetrated two massacres against civilians in Kraljevo and 