Finland will become the 31st member of NATO on Tuesday, immediately preceding a two-day meeting of Allied Foreign Ministers, NATO Secretary General Jens Stoltenberg said on Monday.

"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 for NATO as a whole," he told reporters in Brussels.

This information was confirmed by the office of the President of Finland, stating that the country will become a member of NATO on Tuesday. They added that President Sauli Niinisto will go to Brussels to attend the official ceremony of Finland joining the alliance, which will take place at the NATO headquarters.