The decision to establish the Jastrebarsko children's camp was taken due to the large numbers of Serb children who had been rounded up during anti-Serb massacres conducted by NDH forces since April 1941. Children had also been taken during anti-Partisan operations conducted by German, NDH and other collaborationist forces between April 1941 and June 1942, such as the Kozara Offensive. Their parents and older siblings had often been killed or sent to labour camps both within the NDH and elsewhere in Axis-occupied Europe. Those children who had not been killed in the massacres and counter-insurgency operations were rounded up, as their villages had in most cases been burned to the ground, and they had no means of support.