 At the time, the "Gruppe" was the only fighter unit operating on the left flank of Army Group South, covering the airspace from Belgorod in the north to the Donets Basin in the south, and was equipped with Messerschmitt Bf 109 F-4.On 18 January, Soviet forces launched the Barvenkovo–Lozovaya Offensive which created the Izium salient.On 15 February, III.