The Red Army's offensive continued on 21 November, with forces of the Stalingrad Front achieving penetrations of up to . By this time remaining Romanian units in the north were being destroyed in isolated battles, while the Red Army began to engage flanking portions of the German Fourth Panzer and Sixth Armies. The German 22nd Panzer Division, despite attempting a short counterattack, was reduced to little more than a tank company and forced to withdraw to the southwest. The Soviet 26th Tank Corps, having destroyed a large portion of the Romanian 1st Armored Division, continued its advance to the southeast, avoiding engaging enemy left behind, although remnants of the Romanian 5th Corps were able to reorganize and put up a hastily constructed defense in the hope that it would be aided by the German 48th Panzer Corps. Surrounded by 5th Tank Army on one side and 21st Army on the other, the bulk of 3rd Romanian Army was isolated in the region of Raspopinskaya where General Lascăr took control of the remnants of 4th and 5th Corps, whereas the neighboring 1st Armored Division was still trying to break free and link with 22nd Panzer Division. That day German General Friedrich Paulus, commander of the Sixth Army, received reports that the Soviets were less than from his headquarters; furthermore, there were no remaining units which could contest the Soviet advance. In the south, after a brief halt, the Soviet 4th Mechanized Corps continued its advance north, removing German defenders from several towns in the area, towards Stalingrad. As German forces in and around Stalingrad were at risk, Hitler ordered German forces in the area to establish an "all-around defensive position" and designated forces between the Don and Volga rivers as "Fortress Stalingrad", rather than allow the Sixth Army to attempt to break out. The Sixth Army, other Axis units, and most of the Fourth Panzer Army's German units were caught inside the growing Soviet encirclement. Only the 16th Panzergrenadier Division began to fight its way out. Lack of coordination between Soviet tanks and infantry as the Red Army's tank corps attempted to exploit the breakthrough along the Germans' southern flank allowed much of the Fourth Romanian Army to escape destruction.