The Red Army units immediately formed two defensive fronts: a circumvallation facing inward and a contravallation facing outward. Field Marshal Erich von Manstein advised Hitler not to order the 6th Army to break out, stating that he could break through the Soviet lines and relieve the besieged 6th Army. The American historians Williamson Murray and Alan Millet wrote that it was Manstein's message to Hitler on 24 November advising him that the 6th Army should not break out, along with Göring's statements that the Luftwaffe could supply Stalingrad that "... sealed the fate of the Sixth Army." After 1945, Manstein claimed that he told Hitler that the 6th Army must break out. The American historian Gerhard Weinberg wrote that Manstein distorted his record on the matter. Manstein was tasked to conduct a relief operation, named Operation Winter Storm ("Unternehmen Wintergewitter") against Stalingrad, which he thought was feasible if the 6th Army was temporarily supplied through the air.