The 'Battle of Tornio' was the first major engagement between Finnish and German forces in the 'Lapinsota' Lapland war although there had already been smaller-scale hostilities between the two former co-belligerents against the USSR elsewhere in Finland (1/8 October 1944).

Although open fighting between the Finns and the Germans had begun in the middle of September at Gogland, after the expulsion of the Germans had been demanded by the Soviets as part of their agreement to end the 'Jatkosota' continuation war between Finland and the USSR, relations between the two sides in the north of Finland had remained comparatively good. As earlier planned, in 'Birke' the Germans had already started to remove men and matériel from southern and central Finland to safer positions farther to the north. The Germans' most significant interest in Finnish Lapland was in the retention of the Petsamo area and its strategically important nickel mines. On the other hand, however, German and Finnish troops had been fighting on the same side for three years, and many personal friendships had been forged between the two armies. Up to this time, therefore, there had been very little in the way of overt hostilities between the German and Finnish forces. Until the 'Battle of Tornio', Finnish and German troops had been performing 'autumn manoeuvres' in which the pace of the German withdrawal was matched by the pace of the following Finnish troops with mutual agreement, thereby avoiding open conflict between the two sides.

The Finns, however, were forced by their peace agreement with the USSR to expel the German forces from their country. Thus the Finnish assault on Tornio, on the border with Sweden at the head of the Gulf of Bothnia, was planned and executed to surprise the Germans and open a front in the rear of their evacuation. Kenraaliluutnantti Hjalmar Siilasvuo, commander of the III Armeijakunta (corps) commanded Finnish operations in Lapland and planned an amphibious assault near Tornio to coincide with an overland attack towards Kemi. Both operations had Oulu as their base. The Finns used three cargo vessels each armed with a single anti-aircraft machine gun, and had no air or naval support during the 80-mile (130-km) passage from Oulu to Tornio.

The German forces in the sector of Kemi and Tornio were grouped under Generalmajor Mathias Kräutler’s Division 'Kräutler', otherwise the Divisionsgruppe 'Kräutler', which had been formed in Finland during April 1944 within Generaloberst Dr Lothar Rendulic’s 20^th Gebirgsarmee and was redesignated as the Divisionsstab zbV 140 in September.. These German forces were the 1/139^th Gebirgsjägerbrigade, the 6^th Jägerbataillon, the 6^th SS Gebirgsaufklärungsabteilung and the 6^th SS Schützenbataillon 'Nord'. As a result of Finnish pressure from the south, only the 6^th SS Gebirgsaufklärungsabteilung could be moved toward Tornio while the rest of the available German strength was tied down against the advancing Finns.

The Finns had secured German permission to move the equivalent of one battalion, Eversti Antti Pennanen’s Osasto 'Pennanen' (Detachment 'Pennanen') behind their lines through the subterfuge of protecting the key industrial facilities at Kemi. In addition to this force, the Finnish civic guard had planned an uprising in the border town of Tornio. Using Finnish soldiers currently on leave in the area and one company of air-defence troops, Majuri Thure Larjo managed to take control of Tornio on the western bank of the Torne river and contain the few Germans in the area, but the planned attack on the large German supply depot near Tornio’s railway station on the eastern bank of the river failed. However the Finns were able to send a train to assist the arriving landing force.

Although the rising was not as successful as had been anticipated, it contributed to the confusion on the German side and also made it easier for the landing force to arrive undetected in the port of Röyttä, the outer port of Tornio. The actions of the Osasto 'Pennanen' at Kemi, namely the seizure of the port of Ajos, further misled the initial German response to the landing operation into believing that the Finns were focussing their attentions not on Tornio but on Kemi.

The first elements of the 11^th Jalkaväkirykmentti (infantry regiment) landed unopposed at Röyttä at 07.45 on 1 October and were met by a train that started to move the troops closer to the town. Everstiluutnantti Halsti had planned to move his force swiftly toward Kemi on order to secure the important bridges across the Kemi river but, after learning from other Finnish forces which had secured the town that there could be a complete German battalion in the vicinity, chose more a cautious approach.

Instead of moving toward Kemi, the 11^th Jalkaväkirykmentti therefore moved to secure the German supply depot at Tornio railway station. The arrival of Finnish battalions from Röyttä took Germans by surprise as, up to this time, they had believed that they were dealing with merely a local uprising. Both battalions of the 11^th Jalkaväkirykmentti which had moved toward the station then became tied down in a battle against German troops who fought with almost fanatical resistance.

Still on 1 October, the 11^th Jalkaväkirykmentti’s third battalion was advancing with caution toward Kemi when it encountered and trapped a small German detachment sent to subdue the uprising in Tornio. The Germans were finally realising the extent of the Finnish landing and uprising, but were nonetheless in no position at this moment to take action against the Finns. The Torne river valley was essentially devoid of German forces and their troops at Kemi, under the command of the Division 'Kräutler', comprised only four battalions, most of which had already been committed to delaying against the Finnish advance along the coast from the south.

The Germans responded to the requests of their forces in the Kemi and Tornio areas for reinforcement with the despatch of several units toward the area. One armoured unit, the 2^nd Kompanie of the 211^th Panzerabteilung, was sent from Rovaniemi toward Kemi by rail, and the unit had arrived by the morning of 2 October. Several infantry units were detached from other German groupings and rushed toward Tornio: these included one battalion of the 379^th Grenadierregiment, one battalion of the 206^th Gebirgsjägerregiment and the whole of the Maschinengewehr-Ski-Brigade Finnland. Meanwhile, the Finns chose to reinforce the landing rather than drive hard from the south toward Kemi and started to ship more troops and equipment from Oulu to Tornio. The first of these to arrive was the 53^rd Jalkaväkirykmentti, and thus the Finnish operation changed from a single regiment’s diversionary attack into key operation involving several divisions.

Very late in the evening of 1 October the 11^th Jalkaväkirykmentti captured a German supply depot known colloquially as 'little Berlin', and there found large quantities of alcohol. Order and discipline disappeared from the 2/11^th Jalkaväkirykmenttii, and almost all of the 1/11^th Jalkaväkirykmentti. The newly arriving 2/53^rd Jalkaväkirykmentti was also mistakenly directed to the same location with similar results. The events at 'little-Berlin' meant essentially that Finnish forces in the area lost a whole day and thereby provided the Germans with the time they needed to marshal their forces. The Finns were starting to lose the initiative.

On 3 October the forces the Germans had had managed to group in the area between Tornio and Kemi started moving toward Tornio. Three Finnish battalions (two of the 11^th Jalkaväkirykmentti and one of the 53^rd Jalkaväkirykmentti now faced three German battalions supported by armour and artillery. The initial German attempt in the morning was repulsed and several of their tanks were lost. Both sides now planned to attack, which caused the Finnish flanking battalion to stumble into a German battalion, and both became tied down. However, this did not prevent the main German attack from forcing the Finns to retreat, but the Finns managed to halt the German advance before the situation became too grave. Although the Finns had the advantage of a slight numerical superiority over the Germans in terms of infantry, they had no artillery whatsoever while the Germans could deploy several batteries of artillery as well as several anti-tank guns. In the afternoon of 4 October the Germans attacked again, this time managing to push the Finns to the Raumo river, where the lines stabilised. Further German attempts to cross the Raumo river on 5 October were easily repulsed by the Finns.

On the night of 3/4 October, the German forces to the north of Tornio also attacked Finns, whose forces had advanced to Alavojakkala. The Finns were forced to abandon the fuel depot they had surrounded and had to withdraw farther to the south. Later on 4 October the German forces to the north of Tornio, comprising three battalions of infantry more heavily armed than their Finnish counterparts, exploited their artillery support when facing three Finnish infantry battalions. The Finns expected the main German effort to be made from the direction of Kemi and were ill-prepared for the strong German attack from the north, which advanced rapidly and compelled the Finns to retreat several kilometres before forming new defensive line on the Keropudas river.

Lack of maps, the low state of morale from having to fight an 'unnecessary war', and especially lack of heavy weapons had contributed signally to the Finnish failures.

On 6 October there began the final German effort to drive Finns from the Tornio and regain that town’s vital transport junction. The Germans had deployed six battalions of infantry together with armour and artillery support for the operation, but instead of facing what they believed to be no more than two Finnish infantry regiments they actually facing 10 Finnish battalions of infantry with modest armour (one company of captured Soviet T-26 light tanks had been reactivated) and artillery support. Once again, each side choose to press on with its attacks. The Germans opted to attack simultaneously from the north and east, while the Finns dispatched a full regiment to outflank the Germans to the north of Tornio. What resulted was some of the fiercest fighting of the 'Lapinsota'. The German attack from the north managed to cross the Keropudas river, but was then stopped and tied down by resolute Finnish defence, while the attack from the east failed to drive the Finns from their positions.

The 50^th Jalkaväkirykmentti flanked the Maschinen-Ski-Brigade Finnland, which had been pinned in its attack against the 53^rd Jalkaväkirykmentti, and reached the bank of the Torne river to the north of the German positions. On 7 October the overall situation had deteriorated from bad to worse for the Germans, for not only had their attacks been repulsed but attacking units had suffered heavy losses and the only reserve of the 20^th Gebirgsarmee, a single brigade, had been encircled to the north of Tornio just when the Soviet 'Petsamo-Kirkenes Offensive Operation' in the Arctic started. However, Germans were not the only side in trouble, for the 50^th Jalkaväkirykmentti which had been rushed to the battle, had left most of its equipment in Röyttä and its on-hand supplies had to be carried over swamps or marshy terrain by men. The German attempts to relieve their encircled units did not succeed during 7 October. On the following day the Finns started to mop up the encirclement and attacked from all directions against the surrounded Germans. Though many Germans were taken prisoner in this process, many others managed to escape despite their heavy casualties.

Though the Germans had been able to sortie aircraft to Röyttä at an earlier time, the first serious attack came on 4 October, when the Germans were able to despatch one squadron of Junkers Ju 87 single-engined dive-bomber and ground-attack machines to the port of Röyttä, while Finnish fighters assigned to provide air cover remained grounded by the poor weather at their base farther to the south. Dive-bombers scored several hits to the Finnish transports unloading at the port, sinking Bore IX and Maininki near the pier, which greatly hindered the unloading process. Air raids at Röyttä continued until the end of the fighting in the Tornio region.

Later on 6 October, the first small Finnish navy squadron, comprising the gunboats Hämeenmaa and Uusimaa and the patrol boats VMV 15 and VMV 16, arrived both to provide anti-aircraft fire and to suppress the German battery at Laivaniemi, within range of the port and which had maintained harassing fire on the Finnish effort to unload their transports. The auxiliary gunboat Aunus arrived later. On the same day, several Focke-Wulf Fw 200 four-engined bombers unsuccessfully attacked Ryöttä with Henschel Hs 293 glide bombs.

As a response to the Finns' landing at Tornio and the capture of German troops, the Germans started to take Finnish civilians as hostages: these were 132 persons from Kemi and a further 130 from Rovaniemi. The Germans tried to trade these hostages for the captured Germans. During the fighting at Tornio, a German negotiator arrived with the demand that the Finns release their prisoners and withdraw to Röyttä, or the Germans would execute the hostages. The Finnish response was that such an action would result in the immediate execution of all captured Germans. The German plan thus backfired, since it had negligible impact on Finnish actions and managed only to stain still further the reputations within Finland of the Germans in general and Rendulic in particular. The hostage drama also offered the Finnish media an excellent propaganda tool against the Germans, who realised their mistake and on 12 October abandoned the hostages to the advancing Finns at Jaatila.

Even as the fighting at Tornio continued, the German leadership arrived at the decision to shift from 'Birke' to 'Nordlicht' (iii) and thus abandon most of northern Finland. The Soviet 'Petsamo-Kirkenes Offensive Operation' near Petsamo started soon after Germans had made their decision. Strict marching discipline enforced by the Germans, German motorised units and effective demolition of the local transportation network meant that after the 'Battle of Tornio', the Finnish forces could engage effectively with the withdrawing Germans only at the time and place of Germans' choosing.

The original Finnish plan had been to cut off the German troops around Kemi from all avenues of retreat, but the Germans had been able to secure the road to Rovaniemi and retreat in an orderly fashion. On the other hand, the capture of Tornio in effect sundered German troops in Finland into two parts: one fighting in Tornio river valley, and the other in the Kemi river valley. For lack of roads, the supplies for the Finnish troops around Kemi had to be routed through Rovaniemi, but by 8 October the whole area round Kemi and Tornio had been cleared of German forces.

The German commander in the north, Rendulic, considered the capture of Tornio to be a betrayal by the Finns and ordered the scorched-earth destruction of Lapland in retaliation. By attacking Tornio, the Finnish government had proved to the USSR that it was working actively to remove the German forces from Finland. In addition, the Finnish army had shown that it was both capable and willing to turn its arms on its former co-belligerents.