As a part of the Southwestern Front it became engaged at the beginning of Operation Barbarossa in the Battle of Brody (1941). On 25 June 1941, 12th and 34th Tank Divisions were clearing the hills south of Brody before the whole corps opened its attack later that day. "...Its 34th Tank Division and elements of the 12th Tank Division advanced northwards, cutting the main road between Dubno and Brody. This forced the 16th Panzer Division to wheel round and attack the 34th Tank Division in the area of Kozin, in order to clear the road."