Finnish fireteam near Kemi in October 1944 during the Battle of Tornio, the first major engagment between Germans and Finns.

The Germans had until then been withdrawing steadily towards Norway, ceding their positions to Finnish troops. The German interest was in keeping hold of the Petsamo area and its nickel mines. On the other hand, the German and Finnish troops had been fighting together for three years, and many personal friendships had been forged between the two armies. Thus, until now, there had been very few actual hostilities between the German and Finnish troops.

The Finns, however, were forced by their peace agreement with the USSR to forcibly remove German troops from their territory. Thus the invasion of Tornio was planned and executed to surprise the Germans and open a front behind their backs along the Swedish border. Lieutenant-General Siilasvuo was the officer in charge of the operations in Lapland and planned an amphibious assault near Tornio in time with an overland attack towards Kemi; both operations had Oulu as their base. The Finns used three cargo vessels with an armament of single anti-aircraft machine gun in each ship. They had no air or naval support during the 80 mile sail from Oulu to Tornio. Fortunately for the Finns, because of the stormy weather the German Stukas stayed on ground.

The capture of Tornio took the Germans by surprise. The Finnish Infantry Regiment 11 landed unopposed at Röyttä harbour and took the town of Tornio the same day. The German troops in town were surrounded in a few pockets, so-called motti, until they surrendered. The 15th Jäger brigade advanced to Kemi via Simo, but their progress was slow, because the Germans had laid copious amounts of mines and blown all bridges, with the exception of the Tornio railway bridge that was saved after intervention by the Swedes. Further landings in Tornio the next day came under attack of Stuka bombers of Luftwaffe, but were completed successfully despite casualties of 60 men. German counter attacks (including tanks from Panzer Abteilung 211) were repulsed with the aid of a battery of field artillery that was part of the second landing and fire support from Finnish gunboats which had arrived to the port.

The original Finnish plan had been to cut off the German troops around Kemi from all ways of retreat. However, the German troops were able to secure the road to Rovaniemi and retreat in an orderly fashion. On the other hand, the capture of Tornio effectively cut the German troops in Finland into two parts: one fighting in Tornio river valley, the other in Kemijoki river valley. Due to lack of roads, the supplies to the troops around Kemi would have to be routed through Rovaniemi. This forced the Germans to withdraw their units from Kemi. By October 8 the whole Kemi-Tornio area had been cleared.

The German commander in the North, General Lothar Rendulic considered the capture of Tornio a betrayal by the Finns and ordered the scorched earth destruction of Lapland in retaliation. By attacking Tornio the Finnish government had proven to the Soviet Union that it was working actively to remove the German troops. In addition, the Finnish army had shown that it was capable and willing to turn its arms against the former cobelligerents.