Hitler then decided to resume the advance on Moscow, re-designating the panzer groups as panzer armies for the occasion. Operation Typhoon, which was set in motion on 30 September, saw the 2nd Panzer Army rush along the paved road from Oryol (captured 5 October) to the Oka River at Plavsk, while the 4th Panzer Army (transferred from Army Group North to Centre) and 3rd Panzer armies surrounded the Soviet forces in two huge pockets at Vyazma and Bryansk. Army Group North positioned itself in front of Leningrad and attempted to cut the rail link at Mga to the east. This began the 900-day Siege of Leningrad. North of the Arctic Circle, a German–Finnish force set out for Murmansk but could get no further than the Zapadnaya Litsa River, where they settled down.