[The Soviets] demanded: (1) the lease of a naval base at Hangoe, across the Gulf of Finland from their bases in Estonia; (2) the cession of five islands in the Gulf, which controlled Leningrad strategically by sea; and (3) 2761 square kilometers of land on the Karelian isthmus, the new border to be demilitarized. In return, twice the amount of land farther north was offered.