'Osterei' (ii) was a German and Croat operation, largely by elements of SS-Brigadeführer und Generalmajor der Waffen-SS Karl-Gustav Sauberzweig’s 13th SS Gebirgsdivision 'Handschar' (kroatische Nr 1), to clear the Majevica mountain area of the Yugoslav partisan forces of Marshal Josip Broz Tito in German-occupied Yugoslavia (12/20 April 1944).
The undertaking was launched at 03.00 on 12 April as the 27th SS Gebirgsjägerregiment quickly captured Janja and passed through Donja Trnava to reach its objective, the Ugljevik mine. Here the regiment’s second battalion was involved in combat until the evening of following day, reporting 106 partisans killed, 45 captured and two received as deserters. The 13th SS Gebirgsaufklärungsabteilung linked with the Croat home defence army’s 1st Mountain Brigade, commanded by Colonel Stjepan Peričić, on the western slopes of Majevica, and the 28th SS Gebirgsjägerregiment moved across Mackovac and after fighting around Priboj pushed the 38th Division to the south. The Yugoslav III Corps decided to withdraw its 16th and 36th Divisions from Majevica farther to the south into the area of Birac and Srebrenica while leaving the 38th Division on Majevica, but it was soon clear that the 38th Division also had to withdraw toward Birac on 20 April, the division bringing with it some 200 wounded.