Finland officially joins NATO alliance, Russia vows countermeasures

Finland has officially become a member of NATO, completing a historic security policy shift triggered by Russia's incursion into Ukraine.

Finnish Foreign Minister Pekka Haavisto completed the accession process on Tuesday by handing over an official document to US Secretary of State Antony Blinken at NATO headquarters in Brussels. 

Finland’s blue and white flag was raised among those of its partners outside NATO’s Brussels headquarters. Finland’s president, foreign and defence ministers took part in the ceremony.

The ceremony fell on NATO’s very own birthday, the 74th anniversary of the signing of its founding Washington Treaty on April 4, 1949. It also coincides with a meeting of the alliance's foreign ministers.

Türkiye became the last NATO member country to ratify Finland’s membership protocol on Thursday. It handed over the document officially enshrining that decision to US Secretary of State Antony Blinken before the ceremony on Tuesday.

The event marks the end of an era of military non-alignment for Finland that began after the country repelled an invasion attempt by the Soviet Union during World War Two and opted to try to maintain friendly relations with neighbouring Russia.

But Russia's recent military offensive in another neighbour, Ukraine, which began in February 2022, prompted Finns to seek security under the umbrella of NATO's collective defence pact, which states that an attack on one member is an attack on all.

Russia has already warned that it will bolster its defences near their joint border if NATO deploys any additional troops or equipment to Finland.

In a statement on Tuesday, the Kremlin branded Finland's NATO membership an "assault on our security" and said it represented "the latest aggravation of the situation".

"The expansion of NATO is an assault on our security and Russia's national interests," Kremlin spokesman Dmitry Peskov told reporters.

READ MORE: Finland to become 31st NATO member on Tuesday

Russia angry

The Kremlin has branded Finland's NATO membership an "assault on our security" and said it would take countermeasures.

"The Kremlin believes that this is the latest aggravation of the situation," Kremlin spokesman Dmitry Peskov told reporters.

"The expansion of NATO is an assault on our security and Russia's national interests," he added.

Alarmed by Russia’s military offensive against Ukraine last year, Finland applied to join NATO in May 2022, setting aside years of military nonalignment to seek protection under the organisation’s security umbrella.

In a new statement on Tuesday, NATO chief Jens Stoltenberg said Finland's accession to NATO was a historical event and a direct result of Russia's war on Ukraine, adding the alliance would ensure that Sweden will also become a full-fledged member.

"(Russian) President (Vladimir) Putin had as a declared goal of the invasion of Ukraine to get less NATO," he told reporters ahead of a meeting of the alliance's foreign ministers.

"He is getting exactly the opposite... Finland today, and soon also Sweden will become a full-fledged member of the alliance," he said. 

Neighbouring Sweden also applied, but Türkiye – a NATO member for more than 70 years – says it will not allow Stockholm's membership if it does not address Ankara's legitimate security concerns and fulfil MoU commitments they signed last year.

Finland's accession roughly doubles the length of the border that NATO shares with Russia. Finland shares a 1,340-kilometre (832-mile) border with Russia. 

Moscow said on Monday it would strengthen its military capacity in its western and northwestern regions in response to Finland joining NATO.

Even before Finland formally joined the alliance, its armed forces had drawn closer to NATO and its members.

NATO's surveillance flights by the US and other allied air forces have already begun to circulate in Finnish airspace, the Finnish defence forces said.

On March 24, air force commanders from Sweden, Norway, Finland and Denmark said they had signed a letter of intent to create a unified Nordic air defence to counter the rising threat from Russia.

The move is a strategic and political blow to Russian President Vladimir Putin, who has long complained about NATO’s expansion toward Russia.

READ MORE: Türkiye's parliament set to vote on Finland's NATO bid