Finland formally declared its intent to join NATO Sunday as the historically neutral nation seeks to bolster its security amid Russia’s ongoing incursion into Ukraine.

The nation of roughly 5 million people shares a long border with Russia and the move is likely to escalate already searing regional tensions. //

Finland has been independent since 1917 and entered neutral status after a 1948 treaty with the Soviet Union.

The Nordic nation has a more than 800-mile border with Russia.