During the state of war between Finland and Soviet Russia (1918–1920) the area around Pechenga was occupied by the Finnish forces, and as a result of the Treaty of Tartu in 1920 became a part of Finland as Petsamo. Nickel was discovered in 1921 and began to be exploited commercially in 1935. The area was captured by the Soviets during the Winter War in 1940 but returned to Finland at the conclusion of the war. During the Second World War, between 1941 through 1944, Petsamo was used as a staging post for attacks on Murmansk by Finland and Germany. Aircraft from the British aircraft carrier HMS "Furious" attacked the port on July 30, 1941. The area was captured by the Red Army during the Petsamo–Kirkenes Offensive in 1944 and in 1947, after the subsequent Paris Peace Treaty, incorporated into the Soviet Union.