Early hours of 22 June 1941, under the codename of "Barbarossa" Germany and its allies attacked the Soviet Union. At the time of the attack, approximately 3.6 million German and Axis soldiers with 3600 armoured vehicles, 7100 artillery pieces, and 2700 aircraft crossed the Soviet frontier. The Army Group South manpower had the highest number added non-German Forces; 325000 Romanian troops, later on, augmented with 96000 Hungarian, 62000 Italian, and 45000 Slovakian soldiers. The opposing Soviet forces were better prepared than the other Red Army units along the border. The Kiev Military District, under the leadership of Colonel-General Kirponos, was responsible for manning the 940km long line of defence.