the Organizational Department of the Ukrainian Communist Party's Central Committee, to ensure these orders were carried out. Disposition of forces Six Soviet mechanized corps, with over 2,500 tanks, were massed to take part in a concentric counter-attack through the flanks of Panzer Group 1. The intention was to later attempt a pincer movement from the north (Soviet 5th Army) and south (6th Army) that met west of Dubno in order to trap units of the 6th and 17th German Armies on the northern flank of Army Group South. To achieve this, the 8th Mechanized Corps was transferred from the command of the 26th Army, positioned to the south of the 6th Army, and placed under the command of N. I. Muzychenko's 6th Army. This essentially brought all the mobile assets of the Southwestern Front to bear against the base of von Kleist's thrust toward Kiev. The primary German infantry formation operating on this sector of the front, IV Army Corps (von Schwedler) of the 17th Army (Carl-Heinrich von Stülpnagel) were advancing south-east with the objective of cutting the Lviv-Kiev railway line. German armour At the beginning of Operation Barbarossa, German armor was composed of a mix of Czech and German tanks, as well as small numbers of captured French and British tanks. Furthermore, nearly 50% of the tanks deployed by the Wehrmacht were the Panzer I and Panzer II light tanks. Of the 4000 armored vehicles available to the Wehrmacht, only 1400 were the new Panzer III and Panzer IV. In the first few hours of the invasion, German commanders were shocked to find that some Soviet tanks were immune to all anti-tank weapons in use by the Wehrmacht. During pre-war exercises, Heinz Guderian noted that on their own, tanks were vulnerable to infantry. Furthermore, he also noted that tanks lacked the heavy caliber weapons needed to knock out reinforced concrete bunkers and heavily fortified positions, a role that could only be performed by heavy artillery or air strikes. While dispersing tanks among infantry formations solved many of the tank's weaknesses, it also negated some of their strengths. Therefore, German military theorists concluded that to reach their full potential, armored units needed to be concentrated in their own formations and integrated with mobile artillery, mobile infantry, and close air support. Lastly, Guderian concluded that in order for tanks to be at their peak effectiveness, all armored vehicles must be equipped