Soviet encirclement, the Red Army could continue the "strangulation" of German forces in Stalingrad. Background On 23 November 1942, the Red Army closed its encirclement of Axis forces in Stalingrad. Nearly 300,000 German and Romanian soldiers were trapped in the city and vicinity of Stalingrad by roughly 1.1 million Soviet personnel. Adolf Hitler appointed Field Marshal Erich von Manstein as commander of a new Army Group Don. Composed of the German 4th Panzer and 6th Armies, as well as the Third and Fourth Romanian Armies, Manstein's new army group was between German Army Groups A and B. Instead of attempting an immediate breakout, German high command decided that the trapped forces would remain in Stalingrad and hold out. The encircled German forces were to be supplied by air, requiring roughly of supplies per day. The fleet of 500 Luftwaffe transport aircraft was insufficient for the task. Many of the aircraft were hardly serviceable in the rough Soviet winter; in early December, more German cargo planes were destroyed in accidents than by Soviet fighter aircraft. The 6th Army received less than 20 percent of its daily needs. Furthermore, the Germans were still threatened by Soviet forces which still held portions of the Volga River's west bank in Stalingrad. Given the unexpected size of German forces closed off in Stalingrad, on 23 November Stavka (Soviet Armed Forces High Command) decided to strengthen the outer encirclement preparing to destroy the trapped Axis forces. On 24 November, several Soviet formations began to dig in against possible German incursions from the west. The Soviets also reinforced the encircling forces in order to prevent a breakout by the 6th Army and other Axis units. This tied down over ½ of the Red Army's strength in the area. Planning for Operation Saturn began on 25 November to destroy the Italian 8th Army and cut communications between German forces west of the Don River and those operating in the Caucasus. Planning also began for Operation Koltso (Ring), which aimed at reducing German forces in the Stalingrad pocket. As Operation Uranus concluded, German forces inside the encirclement were too weak to attempt a breakout on their own. Half of their remaining armor had been lost during the defensive fighting and there was a severe lack of fuel and ammunition for the surviving vehicles, given that the Luftwaffe was not able to provide adequate aerial supply. Manstein proposed a counterstrike