While the Stavka was concluding its offensive plans "Generalfeldmarschall" Model was removed from command of the Army Group North Ukraine and replaced by "Generaloberst" Josef Harpe. Harpe's force included two Panzer Armies: the 1st Panzer Army, under "Generaloberst" Gotthard Heinrici and the 4th Panzer Army under "General der Panzertruppen" Walther Nehring. Attached to the 1st Panzer Army was the Hungarian First Army. Harpe could muster only 420 tanks, StuG's and other assorted armoured vehicles. His Army Group comprised around 400,000 men and was supported by the 700 aircraft of Luftflotte 4 (including the veteran air units of "VIII Fliegerkorps") and the 300-400 aircraft of the nearby Luftflotte 6. However, due to the complicated inter-service chain of command, Harpe could not directly control the Luftwaffe units.