'S' (ii) was a German and Croat operation against the partisan forces of Josip Broz Tito in the puppet state of Croatia in Axis-occupied Yugoslavia (24/28 August 1942).

The object of the undertaking was the destruction of a large partisan grouping (6^th 'East Bosnia' Brigade and 'Birčanski' Partisan Detachment) in the area round Sekovići, some 8.75 miles (14 km) to the north-north-west of Vlasenica in eastern Bosnia.

The Axis assembled some 7,000 to 8,000 troops, in which the German contingent was based on Generalleutnant Johann Fortner’s 718^th Division, elements of the 501^st Feldgendarmerieabteilung (mot.), and the 10^th Zug/12^th Panzerkompanie, and the Croat contingent of the 1/3^rd Regiment, 1/8^th Regiment, elements of the 6^th, 7^th, 9^th and 11^th Artillery Groups, 1^st Independent Mountain Artillery Platoon, three or four battalions of the Ustase 'Black Legion'(Ustase Pukovnik Ivo Stipković's 1^st Ustase Brigade and Ustase Pukovnik Rafael Boban’s 5^th Ustase Brigade), Moslem militia units, and one Četnik battalion.

The German and Croat attack began to encircle the partisans in the Sekovići area on 25 August, but the partisans then managed to evade their attackers during the night of 28/29 August, and the operation was therefore a total failure. The Germans admitted the Axis loss of two men killed and eight wounded, and claimed to have killed eight partisans and captured 32.