Finland officially became the 31st member of the North Atlantic Treaty Organization (NATO) alliance on Tuesday.
The Nordic country's participation was sealed during an official ceremony at NATO headquarters in Brussels, which was also attended by US Secretary of State Antony Blinken and NATO Secretary General Jens Stoltenberg.
The historic decision marks a major change in the security landscape in northeastern Europe that adds about 1,300 km to the alliance's border with Russia.
The night before Tuesday's ceremony, Jens Stoltenberg announced the raising of the Finnish flag for the first time at the alliance's headquarters in Belgium.
He said it would be a good day for Finnish security, for Nordic security, and for NATO as a whole.
Earlier, President Vladimir Putin had warned that further NATO expansion would not bring more stability to Europe.
In fact, he also said he would increase forces near Finland if the alliance sent troops or equipment to the new member state.
For the record, Finland and Sweden have officially applied to join the alliance in a move prompted by security concerns from Russia's war in Ukraine.
