The Allies devised a plan to use the Soviet Union's 30 November 1939 attack on Finland as a cover for seizing both the Swedish ore fields in the north, and the Norwegian harbours through which it was shipped to Germany. The plan was to get Norwegian and Swedish permission to send an expeditionary force to Finland across Sápmi, ostensibly to help the Finns. Once in place they were to proceed to take control of Swedish harbours and mines, occupying cities such as Gävle and Luleå and shutting down German access to Swedish ore, presenting Norway and Sweden with a fait accompli.