The Soviets said 13 Red Army soldiers were killed or injured in Mainila shelling.
The day after the attack, Marshall C.G. Mannerheim, commander-in-chief of the Finnish army, denied responsibility for the bombing. He said that Finnish troops were at least 50 kilometres from the border. Mannerheim added that Finnish troops in the area were at a church service at the time of the attack. Furthermore, Finnish border guards had reported hearing shots coming from the Soviet side.
But the Soviets refused to believe the Finns. On November 28, 1939, the Soviets abrogated the non-aggression pact between the two countries. The following day, the Soviets broke off diplomatic relations with Finland. On November 30, 1939, the Red Army launched a surprise assault on several locations in Finland.
The Winter War lasted for 105 days and claimed the lives of around 23,000 Finns. However, Soviet losses were far greater. The exact number is unknown, but some estimate that 130,000 Red Army soldiers lost their lives due to the fighting, hunger and cold.
Finland lost the war, but the Red Army was stunned by the resistance put on by the tiny country. On March 13, 1940, the Soviets and Finns signed a peace treaty. Finland was forced to cede around ten percent of its territory, mainly from eastern Karelia. Over 400,000 Karelians were evacuated from the areas captured by Soviet forces.
War broke out again in June 1941 after less than a year and a half of peace. The Continuation War ended in September 1944.
An admission, decades later
It was not until after the fall of the Soviet Union that Russia admitted the Red Army had orchestrated the Mainila shelling to depict Finland as the aggressor. Prior to the hostilities, the then-Soviet dictator, Josef Stalin, had demanded Finland surrender parts of Karelia in addition to some strategic locations along the Finnish southern coast. The Finns refused.
Archive material suggested that no one was injured in the Mainila shelling.
However, Finland remained an independent nation. Indeed, a survey published last month showed a majority of Finns believe the Winter War saved the nation from tyranny.