During the Finnish-Soviet negotiations ending the Continuation
War (1941–1944) between Finland and the Soviet Union, the
Soviets renounced their claim to Hanko and instead demanded the
right to construct a naval base at Porkkala. The Finns were
forced to agree to a fifty-year lease on Porkkala as part of the
Moscow Armistice concluded on 19 September 1944. Finnish
President Carl Mannerheim regarded this concession as the most
troublesome provision of the armistice agreement because Soviet
forces could easily occupy Helsinki via Porkkala. The Finnish
handover of Porkkala took place ten days after the armistice was
signed, and its 10,000 inhabitants were given eight days to
evacuate the peninsula. On 28 September 1944, Soviet troops
occupied the area. The lease was confirmed in the Paris Peace
Treaty of 10 February 1947. On 24 May 1947, the Soviet Union and
Finland signed the Porkkala-Udd Transit Agreement that permitted
Soviet forces to transit southeastern Finland in order to supply
their recently acquired ba