Finland’s leaders announced Thursday their intention for the country to join NATO “without delay,” a move that would bolster the Western military alliance and which prompted a swift vow of retaliation from Russia.
The Nordic nation, which shares an 810-mile border with Russia, is expected to be given rapid accession to join the alliance that was founded to counter the power of the Kremlin, and neighboring Sweden looks set to follow with its own bid in the coming days.
Moscow said Finland’s move represented a threat and promised to retaliate with “military-technical” action and other measures as Russian President Vladimir Putin confronted the prospect of his war in Ukraine resulting in the very opposite of the goals it was launched to achieve.
"Helsinki must be aware of the responsibility and consequences of such a move," Russia's foreign ministry said in a statement.
Finnish President Sauli Niinistö and Prime Minister Sanna Marin announced their support for the decision in a joint statement early Thursday.
“NATO membership would strengthen Finland’s security. As a member of NATO, Finland would strengthen the entire defense alliance,” they said.
“Finland must apply for NATO membership without delay. We hope that the national steps still needed to make this decision will be taken rapidly within the next few days.”
Finland has traditionally been militarily neutral and enjoyed good relations with Moscow — but the war in Ukraine has led the country to rethink its security and self-determinism.
The move is a sign of European unity and opposition to Putin's aggression, with Western countries acting to counter fears that the Kremlin wants to re-establish Russian power over its neighbors beyond Ukraine.
The end to Kyiv's long-standing desire to join NATO and the removal of Western troops in the region were central to Putin's prewar demands, but Finland joining would double Russia's border with the transatlantic alliance.
Responding to the news, Kremlin spokesman Dmitry Peskov said "another expansion of NATO does not make our continent more stable and secure." Russia’s response would depend on what specific steps NATO takes close to Russian borders, he added.
Russia’s foreign ministry previously warned of “serious military and political consequences” if either of the two countries join the 30-nation alliance.
Asked Wednesday if Finland would provoke Russia by joining NATO, Niinistö said Putin would be to blame. “My response would be that you caused this. Look at the mirror,” he said.
Should Finland become a full NATO member, it would be covered by Article 5, under which all members, including the United States, come to the defense of any other member that is attacked.
Sweden, influenced by the eagerness and speed of its Finnish neighbors, is also widely expected to signal its intention to join the alliance in the coming days.
NATO Secretary-General Jens Stoltenberg said Thursday that Finland would be "warmly welcomed into NATO," adding that the process would be "smooth and swift."
“Finland is one of NATO’s closest partners, a mature democracy, a member of the European Union, and an important contributor to Euro-Atlantic security,” he said.
Member nations are likely to discuss Finland’s application at a summit in Madrid on June 28.
Finland won't formally be covered by Article 5 during its application process, but NATO members are expected to offer it security assurances in the face of any repercussions from Moscow.
Britain agreed to new deals with both Sweden and Finland on Wednesday, pledging to support each country's armed forces should they come under attack.
NATO, formally the North Atlantic Treaty Organization, was founded in 1949 as a way for Western powers to respond to the growing power and influence of the then-Soviet Union.
While Norway was a founding member, Finland has been reluctant until now to fully join the alliance. However, Finland stepped up its collaboration with NATO after Russia's annexation of Crimea in 2014.
With modern, well-equipped armed forces that are compatible with NATO’s operations and standards, and an advanced military intelligence network, analysts see Finland as a natural fit both ideologically and practically.
Public opinion in Finland has swung strongly toward membership in recent weeks, with 76 percent in favor and 12 percent against, according a recent poll from the public broadcaster YLE. Support for joining was typically around 25 percent in polls before the Ukraine war.
Finland fought two wars with Russia between 1939 and 1944 and thwarted an invasion attempt but lost 10 percent of its territory in the process.
Finnish lawmaker Elina Valtonen, chair of the Finnish Parliament’s NATO Assembly, told Sky News on Thursday that the move was a question of defending values.
“Following the events in Ukraine and the brutal invasion of Russia, we feel that it’s just a logical situation now to join NATO and partner up with our friends and allies in the West," she said.
“We are a Western country and we have been a stable democracy for 100 years. Together we are stronger in defending our shared values.”