Finland to join NATO on Tuesday, military alliance chief Jens Stoltenberg says

NATO Secretary-General Jens Stoltenberg has announced Finland will become the 31st member of the world's biggest military alliance on Tuesday, saying he hopes neighbouring Sweden can join in coming months.

The former Norwegian prime minister on Monday said Finland would become a full member of the alliance on Tuesday in what he described as a "historic week".

"(On Tuesday afternoon) we will raise the Finnish flag for the first time here at the NATO headquarters," he said.

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"It will be a good day for Finland's security, for Nordic security, and for NATO as a whole."

Stoltenberg said that Turkey, the last country to have ratified Finland's membership, will hand its official texts to US Secretary of State Antony Blinken on Tuesday. Stoltenberg said he would then invite Finland to do the same.

Finnish President Sauli Niinistö and Defence Minister Antti Kaikkonen will attend the ceremony, along with Foreign Minister Pekka Haavisto.

"It is a historic moment for us. For Finland, the most important objective at the meeting will be to emphasise NATO's support to Ukraine as Russia continues its illegal aggression," Haavisto said in a statement.

"We seek to promote stability and security throughout the Euro-Atlantic region."

The development comes as Finnish voters gave a boost to conservative parties in a weekend election, depriving left-wing Prime Minister Sanna Marin of another term.

Fearing that they might be targeted after Russia invaded Ukraine a year ago, the Nordic neighbours Finland and Sweden abandoned their traditional positions of military non-alignment to seek protection under NATO's security umbrella.

All 30 allies signed Finland's and Sweden's accession protocols. Turkey and Hungary delayed the process for months but have relented on Finland.

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Turkey has sought guarantees and assurances from the two, notably on tackling extremism. Hungary's demands have never been explicit.

NATO must agree unanimously for new members to join.

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