'Osterglocke' was a German unrealised operation against the forces of Marshal Josip Broz Tito in occupied Yugoslavia in support of 'Maigewitter' (iii) (28/30 March 1945).

After completing 'Berggeist', SS-Brigadeführer und Generalmajor der Waffen-SS August Schmidhuber’s 7^th SS Gebirgsdivision 'Prinz Eugen' was moved to Vares in order to support sMaigewitters (iii) by General Hellmuth Felmyss XXXIV Corps zbV with the object of preventing the Yugoslav 2^nd Army from intervening in the fighting round Sarajevo and opening a more effective line of retreat for General Ernst von Leyserss XXI Gebirgskorps from this region.

The 7^th SS Gebirgsdivision started its advance on 28 March, but before it had progressed into a position from which it could have threatened Tuzla, the operation was cancelled on 30 March by the XXI Gebirgskorps as the attack of the XXXIV Corps was weakening and at the same time Yugoslav V sKrajinas Corps was advancing on Kakanj, cutting the main line of retreat from Sarajevo and 363^rd Regiment of Generalleutnant Eugen Bleyerss 181^st Division was cut off in the area of Romanija.

In this dangerous situation, the 7^th SS Gebirgsdivision was divided, its 13^th SS Gebirgsjägerregiment moving to Kakanj and its 14^th SS Gebirgsjägerregiment being sent to Romanija, so ending any possibility of an advance toward Tuzla.