For the battle of battle of Smolensk 1812 see, Battle of Smolensk (1812) The first Battle of Smolensk (, 'Cauldron-battle at Smolensk'; ) was a battle during the second phase of Operation Barbarossa, the Axis invasion of the Soviet Union, in World War II. It was fought around the city of Smolensk between 10 July and 10 September 1941, about west of Moscow. The Ostheer had advanced into the USSR in the 18 days after the invasion on 22 June 1941. The Soviet 16th, 19th and the 20th armies were encircled and destroyed just to the east of Smolensk, though many of the men from the 19th and 20th armies managed to escape the pocket. Some historians have asserted that the cost to the Germans during this drawn-out battle and the delay in the drive towards Moscow led to the victory of the Red Army in the Battle of Moscow of December 1941. Background and planning On 22 June 1941, the Axis nations invaded the Soviet Union in Operation Barbarossa. At first, the campaign met with spectacular success, as the surprised Soviet troops were not able to offer coordinated resistance. After three weeks of fighting, the Germans had reached the Dvina and Dnieper rivers and planned for a resumption of the offensive. The main attack, aimed at Moscow, was carried out by Army Group Centre (Fedor von Bock). Its next target on the way to the Soviet capital was the city of Smolensk. The German plan called for the 2nd Panzer Group (later 2nd Panzer Army) to cross the Dnieper, closing on Smolensk from the south, while the 3rd Panzer Group (later 3rd Panzer Army) was to encircle the town from the north. After their initial defeats, the Red Army began to recover and took measures to ensure a more determined resistance and new defensive line was established around Smolensk. Stalin placed Field Marshal Semyon Timoshenko in command and transferred five armies out of the strategic reserve to Timoshenko. These armies had to conduct counter-offensives to blunt the German drive. The German high command (OKW) was not aware of the Soviet build-up until they encountered them on the battlefield. Facing the Germans along the Dnieper and Dvina rivers were stretches of the Stalin Line fortifications. The defenders were the 13th Army of the Western Front and the 20th Army, 21st Army and the 22nd Army of the Soviet Supreme Command