HELSINKI — Finland received the green light to join NATO when Turkey ratified the Nordic country’s membership late Thursday, becoming the last country in the 30-member Western military alliance to sign off.

All NATO members must vote unanimously to admit a new country. into the alliance. The decision by the Turkish parliament followed Hungary’s ratification of Finland’s bid earlier in the week.

The addition of Finland, which shares a 1,340 kilometer (832 miles) border with Russia, will more than double the size of NATO’s border with Russia.

However, a few more steps and procedures are required before the northern European nation becomes the 31st full NATO member:

ACCEPTANCE LETTERS

Turkey and Hungary dispatch acceptance letters to the United States which is the depositary, or safekeeper, of NATO under the alliance’s 1949 founding treaty. The letters will be filed in the archives of the U.S. State Department, which will notify NATO Secretary-General Jens Stoltenberg that the conditions for inviting Finland to become a member were met.

INVITATION

NATO sends a letter signed by Stoltenberg inviting Finland to join the military alliance.

SIGNATURES

Finland sends its own acceptance document, signed by Foreign Minister Pekka Haavisto, to the U.S. State Department. Finnish President Sauli Niinistö authorized Haavisto to sign the document. Either the Finnish Embassy in Washington or a Finnish government official will deliver the document.

FULL MEMBERSHIP

Once Finland’s membership acceptance document reaches the State Department in Washington, the country officially becomes a NATO member.

FINLAND-SWEDEN

Finland and neighboring Sweden jointly applied for NATO membership in May 2022. The countries, which have close cultural, economic and political ties, planned to enter the alliance simultaneously.

Sweden’s bid, however, has stalled due to opposition from Turkey, whose president has said his country wouldn’t ratify membership before disputes between Ankara and Stockholm were resolved. The Turkish government has accused Sweden of being too soft on groups that it deems to be terror organizations.

Hungary’s parliament also has yet to ratify Sweden’s accession to NATO, and it remains unclear when it will do so.