As part of Operation Typhoon, the 4th Panzer Group was subordinated to the 4th Army under the command of Günther von Kluge. In early October, the 4th Panzer Group completed the encirclement at Vyazma. Kluge instructed Hoepner to pause the advance, much to the latter's displeasure, as his units were needed to prevent break-outs of Soviet forces. Hoepner was confident that the clearing of the pocket and the advance on Moscow could be undertaken at the same time and viewed Kluge's actions as interference, leading to friction and "clashes" with his superior, as he wrote in a letter home on 6 October. Hoepner did not seem to appreciate that his units were very short on fuel; the 11th Panzer Division, reported having no fuel at all. Only the 20th Panzer Division was advancing towards Moscow amid deteriorating road conditions.