The 17th Finnish Division in the corps center was less successful in its attack. The 3rd Soviet Division was able to stop the Finnish attack. The 7th Finnish Division, on the left flank of the VI Corps, had more success. The 13th Infantry Regiment reached and cut the road from Olonets to Petrozavodsk. The 34th Infantry Regiment moved south along this road at the same time as the 44th Infantry Regiment, which had been attached to Task Force Lagus, moved north. Both advances were aimed at the town of Nurmoyla, which was captured on September 7.
The capture of Nurmoyla meant that all road connections to the 3rd Soviet Division were severed. The Soviet division tried to recapture Nurmoyla but failed. It was trapped but most of the personnel managed to slip out of the pocket by abandoning their vehicles and equipment.
After reaching the Svir River, the 7th Finnish Division began clearing both banks. The Soviets had reinforced the area with the 314th Division and the clearing operation was slow. The Finns succeeded in establishing a bridgehead on the southern banks of the Svir by September 22. The bridgehead was approximately 40 kilometers wide and 5–10 kilometers deep.
The Finns were organizing a multidirectional attack against Petrozavodsk, the capital of Soviet Karelia. The 1st Light Infantry Brigade was approaching the city from the south along the railroad. The VII Corps on the left wing of the Army of Karelia, reinforced by the 4th Division from the Karelian Isthmus, was moving against Petrozavodsk from the west. The corps captured the important road junction at Krasnaya Pryazka, 40 kilometers west of Petrozavodsk on September 8. Major General Hägglund sent the 1st Division on a very strenuous march eastwards against Petrozavodsk through the great trackless forest south of the road, a task that it completed with considerable speed. Group Oinonen and II Corps, under Major General Laatikainen, which had been transferred to East Karelia from the Karelian Isthmus, approached Petrozavodsk from the northwest.
The concentric Finnish attack on Petrozavodsk began on September 18. The Soviets soon recognized the gravity of the situation and began to evacuate forces from the city. By the time the 11th Finnish Division cut the main road and railroad leading north from the city on September 30, most of the Soviet troops had been evacuated by sea across Lake Onega. The city fell to Finnish troops on October 1, 1941.
The 3rd Soviet Division, which had offered stubborn resistance to the northward drive along the road and railroad, now found itself completely isolated. Equipment and vehicles had been abandoned and the remaining troops began a southward trek through the forest with the Finnish 30th Infantry Regiment in pursuit. Only a few hundred men from the division managed to escape two weeks later across the Svir River.
The VI Corps had meanwhile crossed Svir River at its Lake Onega end. The Finnish bridgehead across the Svir was expanded to 100 kilometers in width and 20 kilometers in depth. This expansion was necessitated by the need for better defensive positions before the onset of winter.
Mannerheim decided the Army of Karelia should continue the northward offensive towards the town of Medvezhyegorsk (Karhumäki) despite signs of an early and hard winter. The first objectives were the string of lake isthmuses along the Suna River. The Finnish divisions advancing from Petrozavodsk and Porosozero (Porajärvi) were able to maneuver the Soviets into the rough lake and river country between Medvezhyegorsk and Lake Seg. II Finnish Corps reached and cleared the Suna River line on October 19, and units from this corps also reached the area west of Lake Seg. Finnish forces from the south captured Kondopoga (Kontupohja) on November 3 and met the forces from the north at Lizhma Lake on November 5. Soviet forces tried desperately to prevent this juncture. When they failed to stem the multi-pronged Finnish advance, they withdrew to Medvezhyegorsk.
Finnish troops were beginning to show the strain of months of continuous operations. The early onset of winter did not help. It appeared that their offensive strength had reached its limit. The planned transfer of one division and several heavy artillery batteries to East Karelia from the Karelian Isthmus for the attack against Medvezhyegorsk could not be carried out because of rail transportation problems.21 The terrain around Medvezhyegorsk had become almost impassable due to deep snow. An attack by the 4th Division from the north was stopped only four kilometers from the town center. The attack by the 1st Division was also stopped. It appeared that the Finnish offensive had come to an end in front of Medvezhyegorsk.
At the urgings of their corps commander, General Laatikainen, the Finns began another supreme effort on November 29, successfully breaching the outer Soviet defenses on December 2. The Finns launched their final attack on the morning of December 5 with the 4th Division from the north and the 1st Light Infantry Brigade, followed by the 2nd Light Infantry Brigade, from the west. Advancing in bitter cold, and with snow up to their knees, the Finns breached the final defensive line and entered Medvezhyegorsk. The town of Povents (Poventsa) on the Stalin Canal was captured by Colonel Lagus’ 1st Light Infantry Brigade on December 6, 1941. A large Soviet force was surrounded south of Medvezhyegorsk and destroyed on December 8.
The Finns established a defensive line on the Maaselkä, the watershed between the Gulf of Finland and the White Sea. This watershed ran across the isthmus between Lake Seg and the northern point of Lake Onega. The Finnish defensive positions overlooked this isthmus. With the capture of Medvezhyegorsk, active operations ended on the Finnish front.
The Finnish victories in the south were impressive. But the cost in lives was high. Total Finnish casualties by the end of the year had reached 75,000, including 25,500 who had paid the ultimate price. Vehviläinen points out that the number who fell was almost equivalent to a whole year group of conscripts.22
There are some aspects of the war in southern Finland that cannot be covered in the same detail as the land operations because of space considerations. They were nevertheless important and deserve to be mentioned. Both naval operations in the Gulf of Finland and air operations fall into this category.
The small Finnish Navy was divided into two branches, coastal artillery, and naval ships. The latter were few in number—two coastal defense ships, five submarines, and a number of smaller ships. German naval units in the Baltic had the primary mission of protecting the sea route for the iron ore that came from Sweden. Support of operations in Finland was accorded a lower priority.
Recognizing their own inferiority to the superior Soviet Navy, the Finns and Germans had agreed before the war to rely primarily on mine warfare to neutralize the enemy surface fleet. This fleet was substantial—2 battleships, 2 light cruisers, 19 destroyers, and 68 submarines. In addition there were over 700 naval aircraft. Furthermore, the Soviet naval base at Hanko was to be besieged from both land and sea. Belts of mines were laid in the Baltic and Gulf of Finland beginning shortly before the commencement of hostilities. The German/Finnish tactics proved very successful and the Soviets were unable to make use of their naval superiority. The fleet remained bottled up in the Bay of Kronstadt. The Finnish Navy thereby accomplished its primary mission of neutralizing the much superior Soviet fleet.