sentences:  Army Group North, commanded by Field Marshal Wilhelm Ritter von Leeb, and staging in East Prussia prior to the commencement of the offensive, was the northern of three army groups participating in Operation Barbarossa, the German invasion of the Soviet Union.Army Group North controlled the 18th Army and the 16th Army, along with the 4th Panzer Group (General Erich Hoepner).The Germans had 20 infantry divisions, three Panzer and three motorized infantry divisions.