Army Group Don
Spurred on by this success, the Red Army planned a series of follow-up offensives in January and February 1943 intended to decisively beat the German forces in southern Russia. After the destruction of the remaining Hungarian and Italian forces during the Ostrogozhsk–Rossosh Offensive, Operation Star and Operation Gallop were launched to recapture Kharkov and Kursk and to cut off all German forces east of Donetsk. Those operations succeeded in breaking through the German lines and threatened the whole southern part of the German front. To deal with this threat, Army Group Don, Army Group B, and parts of Army Group A were united as Army Group South ("Heeresgruppe Süd") under Manstein's command in early February.