Finland has confirmed that it will apply for Nato membership, abandoning the neutral status the country has held since the end of World War Two.
The move comes despite warnings from Russian president Vladimir Putin, who told his Finnish counterpart that joining Nato would be a “mistake”.
President Sauli Niinisto called it a “historic day”. He says the shift in policy is in response to Russia’s invasion of Ukraine.
Nato foreign ministers say they want a rapid accession process for Finland.
Sweden could also announce its intention to join as soon as Monday.
Finland shares a 1,300-km (810-mile) border with Russia. Until now, it has stayed out of Nato to avoid antagonising its eastern neighbour.