The massacre at Kraljevo , as well as a similar and nearly concurrent massacre in nearby Kragujevac , was met with outrage by the Serbian puppet government , which responded with pleas , interventions and threats of resignation . The killings led German military commanders in Serbia to question the efficacy of mass reprisal shootings , as they pushed thousands of Serbs into the hands of anti-German guerrillas . The killing of airplane factory workers in Kraljevo convinced the OKW that arbitrary shootings of Serbs not only incurred a significant political cost but were also counterproductive . The ratio of 100 executions for one soldier killed and 50 executions for one soldier wounded was reduced by half in February 1943 , and removed altogether that autumn . Henceforth , each individual execution had to be approved by Special Envoy Hermann Neubacher
massacre
Kragujevac massacre
Kraljevo massacre