Soviet military intelligence on covert German - Finnish military cooperation shortly before Great Patriotic War (1940-1941)

On the eve of the Great Patriotic War, the Soviet intelligence services paid increased attention to the military and political situation in Finland. The Soviet intelligence activity was well organized on its territory. As a result, the Soviet intelligence in the second half of the 1940 and at the beginning of the 1941 was able to collect extensive evidences on growing dynamics of military cooperation between Germany and Finland, as well as on deployment of German troops in the northern wing of the Soviet - Finnish border. Due to this information, the Soviet military command was on guard concerning the development of military situation. As a result, the bombing of the Finnish territory by Soviet air forces on June 25, 1941 was caused by military activities of German aviation that used Finland as its military base. The air strike was also conditioned by high quality operational awareness on German - Finnish military cooperation in 1940-1941