When Operation Barbarossa, the invasion of the Soviet Union, commenced in late June 1941, the 16th Army controlled seven infantry divisions. Assigned to Army Group North, and operating on its southern flank during the advance into the Baltic States and Russia, it captured Staraya Russa in August. By December, the 16th Army had been considerably expanded, and Busch now had nine infantry divisions along with two motorised divisions, with one more in reserve, under his command. When the Red Army began its winter offensive in January 1942, several parts of his army became encircled and Staraya Russa was nearly lost. Busch had to resort to his reserve to ensure his forces could hold onto the city. The commander of Army Group North, Generaloberst Georg von Küchler, became dissatisfied with Busch's performance and wanted to relieve him of command. Permission to do so was denied. The Red Army offensive shifted focus towards Army Group Centre which relieved the pressure on the 16th Army. Busch was able to relieve his encircled troops although it took several months and required his army to be reinforced.