Finland's leaders support NATO membership, Sweden expected to follow suit
Kremlin spokesperson said NATO expansion considered a threat, warns of response
Finland said on Thursday it would apply to join NATO "without delay," with Sweden expected to follow, as Russia's invasion of Ukraine looked set to bring about the very expansion of the Western military alliance that Russian President Vladimir Putin aimed to prevent.
The decision by the two Nordic countries to abandon the neutrality they maintained throughout the Cold War would be one of the biggest shifts in European security in decades. Moscow called Finland's announcement a direct threat to Russia and threatened retaliation, including unspecified "military-technical" measures.
It came even as Russia's war in Ukraine was suffering another big setback, with Ukrainian forces driving Russian troops out of the region around the second-largest city Kharkiv, the fastest Ukrainian advance since forcing Russia to withdraw from the capital and northeast more than a month ago.
NATO Secretary-General Jens Stoltenberg said the Finns would be "warmly welcomed" and promised a "smooth and swift" accession process. French President Emmanuel Macron said he fully supported Finland's choice to join the alliance.
Finland's 1,300-kilometre border will more than double the length of the frontier between the U.S.-led alliance and Russia, putting NATO guards a few hours' drive from the northern outskirts of St. Petersburg.
"Finland must apply for NATO membership without delay," Finnish President Sauli Niinisto and Finnish Prime Minister Sanna Marin in a joint statement, hoping steps to take the decision would "be taken rapidly within the next few days."
Asked whether Finland's accession posed a direct threat to Russia, Kremlin spokesperson Dmitry Peskov said, "Definitely. NATO expansion does not make our continent more stable and secure."
"This cannot fail to arouse our regret, and is a reason for corresponding symmetrical responses on our side," Peskov added.
Russia's Foreign Ministry said Moscow would be forced to take "retaliatory steps, both of a military-technical and other nature," giving no further details. Russian officials have spoken in the past about potential measures including stationing nuclear-armed missiles on the Baltic Sea.
Asked on Wednesday if Finland would provoke Russia by joining NATO, Niinisto said: "My response would be that you caused this. Look at the mirror."
Five diplomats and officials told Reuters that NATO allies expect both countries to be granted membership quickly, paving the way for an increased troop presence in the Nordic region to defend them during a one-year ratification period.
U.K. pledges to help if Finland attacked
A day earlier, British Prime Minister Boris Johnson visited both Finland and Sweden to sign a military co-operation agreement.
The U.K. pledged on Wednesday to come to the aid of Sweden and Finland if the two Nordic nations came under attack.
In 2017, Sweden and Finland joined the British-led Joint Expeditionary Force, which is designed to be more flexible and respond more quickly than the larger NATO alliance. It uses NATO standards and doctrine, so it can operate in conjunction with NATO, the United Nations or other multinational coalitions. Fully operational since 2018, the force has held a number of exercises both independently and in co-operation with NATO.
Since Russia's invasion of Ukraine on Feb. 24, Finland and Sweden have been pondering whether to abandon their historic, decades-old neutrality and join the 30-member NATO.
Should Finland become a NATO member, it would mean the biggest change in the Nordic country's defence and security policy since the Second World War.
With files from The Associated Press