Finland will officially become a member of the military alliance on Tuesday (4 April) as foreign ministers gather for their meeting in Brussels, NATO Secretary-General Jens Stoltenberg told reporters on Monday.

Finland and Sweden jointly applied for NATO membership in May 2022, shortly after the Russian invasion of Ukraine. But the process has been stalled due to hesitance from some members, including Hungary and Turkey, over the Swedish application.

Turkey has been asking Sweden to taste up its anti-terrorism legislation and take steps against supporters of Kurdish militants and members of the network Ankara holds responsible for a 2016 coup attempt, which it sees as a terrorist organisation.

However, Finland’s accession was green-lighted last week by the Turkish Parliament, clearing the last major hurdle while Sweden remains on a different track.

“We will raise the Finnish flag for the first time here at NATO headquarters. It will be a good day for Finland’s security, for Nordic security and NATO as a whole,” Stoltenberg told reporters on Monday (3 March).

“Last year, Allies made the historic decision to invite Finland and Sweden to become members” at the NATO Summit in Madrid in June.s

Less than a year later, Helsinki will now become a member, which will be “the fastest ratification process in NATO’s modern history”, Stoltenberg added.

On Tuesday, Turkey will deposit the ratification agreement “with the US, at the NATO Headquarters”, Stoltenberg explained. Then, he will “notify Finland”.

The Finnish Foreign Minister Pekka Haavisto will then give Finland’s instrument of accession to the US State Department, represented by the Secretary of State Antony Blinken.

A flag-raising ceremony will then occur in front of the NATO headquarters in Brussels aT 15:30 CET, which will mark Finland’s official accession to NATO.

Stoltenberg mentioned the benefits of Finland’s presence in the alliance, noting it will bring “substantial military forces” and has been “investing in new advance modern 5th generation aircraft, the F-35, for more than 60” pieces, he added. “They’ve trained and built a large army and maintained a high level of readiness”.

It is also “among one of the few countries which didn’t reduce its investment in forces after the Cold War”, unlike many NATO Allies, which are now speeding up investment against the backdrop of the war in Ukraine.

So far, the Finns have not asked for a reinforcement of their 1340 km long border with Russia by NATO Allies, according to people with knowledge of the situation. Meanwhile, its accession will see the Alliance double its land border with Russia.

However, Sweden remains an “invitee” to the NATO meeting until its accession process is finished and its membership been green-lighted by all 30 of the Alliance’s parliaments, with just Hungary and Turkey remaining.

“All allies agree that Sweden’s accession will have to be completed quickly”, Stoltenberg said. It is a “priority for me that it happens as soon as possible”, he added.

It is nevertheless unlikely Ankara will give its green light before the elections in Turkey in mid-May and the entry into force of the anti-terrorism law on June 1st, NATO officials concede.

“We should not leave the impression Sweden is left alone”, the secretary-general said about it already participating in most of the Alliance’s meetings. “Allies are ready to act”, he added, “it is inconceivable if there is any threat of attacks against Sweden without allies reacting, even more so with Finland as a member”.