European theatre of World War II
Swedish iron ore was an important economic factor in the European theatre of World War II. Both the Allies and the Axis were keen to gain control of the mining district in northernmost Sweden, surrounding the mining towns of Gällivare and Kiruna. The importance of this issue increased after other sources of iron were cut off from Germany by the Allied naval blockade during the Battle of the Atlantic. Both the planned Anglo-French support of Finland in the Winter War, and the following German occupation of Denmark and Norway during Operation Weserübung were to a large extent motivated by the wish to deny their respective enemies iron critical for wartime production of steel.