This was the Yugoslav designation for the Axis offensive against the partisan forces of Josip Broz Tito in the eastern part of Bosnia in Axis-occupied Yugoslavia (17/23 January 1942).
This 'Second Enemy Offensive', which consisted of three consecutive German-led operations, namely ‘Südost Kroatien’ and ‘Ozren’ (ii) against the partisan forces in eastern Bosnia, and ‘Prijedor’ to relieve beleaguered German and Croat forces in north-western Bosnia, was a major counter-insurgency operation. In eastern Bosnia, the partisan troops avoided encirclement and were forced to retreat over Igman mountain near Sarajevo.
The main object of the 'Second Enemy Offensive' was to surround, trap and destroy the partisan forces in Romanija, Birač and Glasinac. Part of the overall plan was for a stop line to be established along the line linking Kalinovik, Goražde and Višegrad by Italian forces, but these were unable to comply as they were fully occupied in the defence of their own garrisons, but the German forces were nonetheless supported by a number of Ustaše and a few Italian units.
In the village of Bijele Vode, on 21 January, the Axis forces attacked the 2/1st Proletarian Brigade, which lost 14 men, and on the same day the Germans in Pjenovac attacked a small railway station. During this battle, the 1st Proletarian Brigade and the 'Romanija' Partisan Detachment suffered 59 casualties including the commander of the 'Romanija' Partisan Detachment, Slaviša Vajner Čiča, and the commander and political commissar of the ‘Šumadija’ Battalion, Milan Ilić and Dragan Pavlović Šilja. The partisans’ main headquarters and elements of the 1st Proletarian Brigade retreated across Glasinac and Jahorina to reach Foča. Most of the brigade had tried to hold the village Srednje, and had therefore to choose another way. It selected the least expected way, very close to Sarajevo, by a retreat over Igman mountain in temperatures as low as -26° F (-32° C). The brigade suffered severe losses to the cold, 172 of the 600 men who crossed the mountain suffering frostbite injuries.