the Karelian Isthmus be moved westward to a point only east of Viipuri () and that Finland destroy all existing fortifications on the Karelian Isthmus. Likewise, the delegation demanded the cession of islands in the Gulf of Finland as well as Rybachy Peninsula (). The Finns would also have to lease the Hanko Peninsula for 30 years and to permit the Soviets to establish a military base there. In exchange, the Soviet Union would cede Repola and Porajärvi from Eastern Karelia, an area twice the size as that of the territory demanded from Finland. The Soviet offer divided the Finnish government but was eventually rejected with respect to the opinion of the public and Parliament. On 31 October, Soviet Foreign Minister Vyacheslav Molotov publicly announced Soviet demands in public to the Supreme Soviet. The Finns made two counteroffers to cede the Terijoki area to the Soviet Union. That would double the distance between Leningrad and the Finnish border but was far less than the Soviets had demanded. The Finns would also cede the islands in the Gulf of Finland. The Finnish delegation returned home on 13 November and took for granted that the negotiations would continue. Shelling of Mainila and Soviet intentions On 26 November 1939, an incident was reported near the Soviet village of Mainila, near the border with Finland. A Soviet border guard post had been shelled by an unknown party resulting, according to Soviet reports, in the deaths of four and injuries of nine border guards. Research conducted by several Finnish and Russian historians later concluded that the shelling was a false flag operation since there were no artillery units there, and it was carried out from the Soviet side of the border by an NKVD unit with the purpose of providing the Soviets with a casus belli and a pretext to withdraw from the non-aggression pact. Soviet war games held in March 1938 and 1939 had been based on a scenario in which border incidents taking place at the village of Mainila would spark the war. Molotov claimed that the incident was a Finnish artillery attack. He demanded that Finland apologise for the incident and to move its forces beyond a line from the border. Finland denied responsibility for the attack, rejected the demands and called for a joint Finnish–Soviet commission to examine the incident. In turn, the Soviet Union claimed that the Finnish response was