Russia warned Thursday that it would not hesitate to retaliate should Finland join NATO, heightening fears that the war in Ukraine could escalate into a direct confrontation between nuclear powers.\r\n\r\nMoscow\u0026#039;s threat came just hours after Finnish leaders said that the historically neutral Nordic country, which shares an 830-mile border with Russia, should apply immediately for membership in the U.S.-led military alliance.\r\n\r\n\u0022Finland must apply for NATO membership without delay,\u0022 President Sauli Niinisto and Prime Minister Sanna Marin said in a joint statement. \u0022We hope that the national steps still needed to make this decision will be taken rapidly within the next few days.\u0022\r\n\r\nIn response, Russia\u0026#039;s foreign ministry said in a statement that \u0022Finland\u0026#039;s accession to NATO will cause serious damage to bilateral Russian-Finnish relations and the maintaining of stability and security in the Northern European region.\u0022\r\n\r\n\u0022Russia will be forced to take retaliatory steps, both of a military-technical and other nature, in order to neutralize the threats to its national security that arise from this,\u0022 the statement added.\r\n\r\nMoscow did not specify what \u0022retaliatory steps\u0022 it would take, but Kremlin spokesperson Dmitry Peskov told reporters that \u0022everything will depend on how this expansion process plays out, the extent to which military infrastructure moves closer to our borders.\u0022\r\n\r\nFormer Russian President Dmitry Medvedev, now deputy chairman of the country\u0026#039;s security council, said\u0026nbsp;Thursday that the exercises of alliance members \u0022near our borders increase the likelihood of a direct and open conflict between NATO and Russia.\u0022\r\n\r\n\u0022Such a conflict always has the risk of turning into a full-fledged nuclear war,\u0022 he added. \u0022This will be a disastrous scenario for everyone.\u0022\r\n\r\nSince Russia invaded Ukraine in late February, lawmakers in Finland and neighboring Sweden have been mulling whether to jettison their long-standing neutrality and join the 30-member NATO. Both countries are expected to announce formal decisions on Sunday.\r\n\r\nAccording to CNBC: \u0022If Finland does join the military alliance, the land border that Russia shares with NATO territories would roughly double. Russia has land borders with 14 countries and five of them are NATO members: Latvia, Estonia, Lithuania, Poland and Norway.\u0022\r\n\r\nRussia\u0026#039;s foreign ministry argued Thursday that \u0022the goal of NATO, whose member countries vigorously convinced the Finnish side that there was no alternative to membership in the alliance, is clear—to continue expanding towards the borders of Russia, to create another flank for a military threat to our country.\u0022\r\n\r\nAnti-war advocates have long contended that NATO enlargement—and especially its expansion into former Soviet and Warsaw Pact nations—is highly provocative toward Russia.\r\n\r\nMoscow warned last month that if Finland and Sweden join NATO, Russia would respond by strengthening its military capabilities along its borders with alliance members—including the deployment of additional nuclear weapons to the Baltic region.\r\n\r\n\r\n\r\nRussia\u0026#039;s war on Ukraine has boosted public support for NATO membership among Finns and Swedes.\r\n\r\nAccording to the Associated Press, \u0022The latest opinion poll conducted by Finnish public broadcaster YLE showed earlier this week that 76% of Finns are in favor of joining NATO, a big change from earlier years when only 20-30% of respondents favored such military alignment.\u0022\r\n\r\n\u0022NATO Secretary-General Jens Stoltenberg has said the military alliance would welcome Finland and Sweden—both of which have strong, modern militaries—with open arms and expects the accession process to be speedy and smooth,\u0022 AP reported. \u0022NATO officials say the Nordic duo\u0026#039;s accession process could be done \u0026#039;in a couple of weeks.\u0026#039;\u0022\r\n\r\nAgnes Hellström of the Swedish Peace and Arbitration Society, however, told Democracy Now! last month that peace activists \u0022don\u0026#039;t think it would make us safer or the world more secure.\u0022\r\n\r\n\u0022It would make us part of a nuclear doctrine,\u0022 she said, \u0022and our possibility to be a voice for democracy, prevention, and disarmament would decrease.\u0022\r\n\r\nThis story has been updated with comment from\u0026nbsp;Dmitry Medvedev.