NATO members on Tuesday signed the accession protocols for Finland and Sweden to join the military alliance.
Both countries submitted their applications in May, breaking longstanding non-aligned stances in response to Russia's invasion of Ukraine.
"This is a good day for Finland and Sweden, and a good day for NATO. With 32 nations around the table, we will be even stronger and our people will be even safer as we face the biggest security crisis in decades," NATO Secretary-General Jens Stoltenberg said.
He added that 'NATO's door remains open to European democracies who are ready to and willing to contribute to our shared security."
With the accession protocols signed, each of NATO's 30 member countries now have to ratify them according to their individual national procedures.
Both Finland and Sweden have a history of working with NATO as partner countries, including attending NATO meetings and participating in military exercises.
"As a future member of the alliance, Sweden will contribute to the security of all allies," Swedish Foreign Minister Ann Linde said at the start of Tuesday's meeting.
Finland's Foreign Minister Pekka Haavisto said his country looks forward to working with NATO allies to safeguard a "secure and prosperous Euro-Atlantic region."
"Together we are stronger in defending the rules-based international order and the principles of democratic freedom and rule of law," Haavisto said.
Some information for this report came from The Associated Press and Reuters