At the end of 1941, there were six Partisan detachments in eastern Bosnia, with about 7,300 fighters operating in the Majevica, Ozren, Birač, Romanija, Zvijezda and Kalinovik areas. In January 1942, the Romanija detachment had borne the brunt of Operation Southeast Croatia and had been effectively destroyed. Many Partisan fighters were Serb peasants who took to the forests and mountains to defend their families and villages against the Ustaše; few were ideologically committed to the Partisan cause. The Chetnik forces in eastern Bosnia had not opposed the Axis offensive. Many had withdrawn across the Drina river into the Territory of the Military Commander in Serbia to avoid engagement with German and NDH forces.
