FINLAND joined the NATO military alliance on Tuesday, dealing a major blow to Russia with a historic realignment of the continent triggered by Moscow’s invasion of Ukraine. The Nordic country’s membership doubles Russia’s border with the world’s biggest security alliance and represents a major change in Europe’s security landscape: The nation adopted neutrality after its defeat by the Soviets in World War II. But its leaders signalled they wanted to join the alliance just months after Russian President Vladimir Putin’s invasion of Ukraine sent a shiver of fear through Moscow’s neighbours. The move is a strategic and political blow to Putin, who has long complained about NATO’s expansion toward Russia and partly used that as a justification for the invasion. Russia warned that it would be forced to take “retaliatory measures” to address what it called security threats created by Finland’s membership. It had also warned it would bolster forces near Finland if NATO sends any additional troops or equipment to what is its 31st member country.

The alliance says it poses no threat to Moscow. Neighbouring Sweden, which has avoided military alliances for more than 200 years, has also applied. But objections from NATO members Turkiye and Hungary have delayed the process.

Alarmed by Moscow’s invasion of Ukraine last year, Finland, which shares a 1,340 kilometre (832 mile) border with Russia, applied to join in May, setting aside years of military non-alignment to seek protection under the organisation’s security umbrella. “I’m tempted to say this is maybe the one thing that we can thank Mr. Putin for because he once again here precipitated something he claims to want to prevent by Russia’s aggression, causing many countries to believe that they have to do more to look out for their own defence and to make sure that they can deter possible Russian aggression going forward,” US Secretary of State Antony Blinken said just before accepting the documents that made Finland’s membership official. The US State Department is repository of NATO texts concerning membership. Earlier, Russia’s Foreign Ministry said the country “will be forced to take military-technical and other retaliatory measures to counter the threats to our national security arising from Finland’s accession to NATO.”