In 1939 the Soviet Union attacked Finland starting the Winter War. The Moscow Peace Treaty of 1940 handed the eastern half of Finnish Karelia to the Soviet Union. About 400,000 people, virtually the whole population, had to be relocated within Finland. In 1941 Finland attacked the Soviet Union alongside the Axis powers as co-belligerents. The Finnish military administration in Eastern Karelia administered the region during 1941–1944.