Finland's accession marks the end of an era of military non-alignment while roughly doubles the length of the border that NATO shares with Russia.
Finland's foreign minister will hand over the formal accession papers to US Secretary of State Antony Blinken, the keeper of NATO's founding treaty, and President Sauli Niinisto is expected to speak at the event.
With 99 percent of the votes counted, Petteri Orpo's party was credited with 48 of the 200 seats in parliament, the far-right with 46 and the Social Democrats with 43, according to election data.
The election comes just days after Türkiye approved the Nordic nation's bid to join NATO, but its main proponent and Social Democratic Prime Minister Sanna Marin faces a tough challenge in her bid for a second term.
The addition of Finland, which shares a 1,340 kilometre (832 miles) border with Russia, will more than double the size of NATO’s border with the world's largest country in terms of land area.
Türkiye's ratification leaves Finland, which shares a long border with Russia, only a few technical steps away from becoming 31st member of the world's most powerful military bloc.
Türkiye's ratification will leave Finland, which shares a long border with Russia, with only a few technical steps before it becomes the 31st member of the world's most powerful military bloc.
A large majority of lawmakers -182 votes for versus six against - approved the accession of the Nordic country into the military alliance.
Turkish presidential spokesperson Ibrahim Kalin says that the door is not closed to Stockholm now, but how the process will progress, its pace, and when it will be completed depends on Sweden's steps.
Finland and Sweden formally applied to join NATO last May but Türkiye, a longstanding NATO member, asked the two Nordic states to take concrete action against terror groups like the PKK and FETO.
Turkish President Recep Tayyip Erdogan announced that he will ask Türkiye's parliament to vote on Finland's NATO application following his meeting with his Finnish counterpart in Ankara on Friday.
Ankara will fulfil its promise and "run the process" for Finland's NATO membership bid, Turkish President Recep Tayyip Erdogan says.
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