In June, the Wehrmacht was preparing for Operation Barbarossa, the German invasion of the Soviet, and consolidating its forces near the border established in the German–Soviet Frontier Treaty. On 4 June, III. "Gruppe" arrived at Suwałki before being redeployed to Sobolewo on 12 June. At the start of the invasion, JG 27, with the exception of I. "Gruppe", was subordinated to VIII. "Fliegerkorps" (8th Air Corps) and was deployed in the northern sector of Army Group Centre. On 22 June 1941, the opening day of Operation Barbarossa, III. "Gruppe" flew many ground support missions against Soviet airfields and forces, its first just past 03:00. Later in the day, Kageneck shot down a Tupolev SB bomber south of Vilnius.