Soviet forces grouped together around Stalingrad. Violent fighting to attack the Germans began. Operation Winter Storm ("Operation Wintergewitter"), the German attempt to rescue the trapped army from the south, was at first successful. By 19 December, the German Army had pushed to within 48 km (30 mi) of Sixth Army's positions. Some German officers asked Paulus go against Hitler's orders and try to escape out of the Stalingrad. Paulus refused. On 23 December, Manstein's forces had to defend themselves from new Soviet attacks.