NATO on Wednesday invited Macedonia to start talks to join the alliance after Skopje reached a deal with Greece in a long-running row over the country's name.
Alliance chief Jens Stoltenberg said Macedonia would be able to become NATO's newest member, provided the new name was approved in a referendum later this year.
Skopje reached an agreement with Athens last month to rename the country the Republic of North Macedonia in a bid to resolve a dispute that has poisoned relations between the two countries since 1991.
"NATO's door is and will remain open: we agreed to invite the government in Skopje to start accession talks," Stoltenberg said after NATO leaders approved the move at a summit in Brussels.
"Once all national procedures have been completed to finalise the name agreement, the country will join NATO as our 30th member."
Macedonian Prime Minister Zoran Zaev hailed the announcement as a "great, historic day" for his country.
"Our partners and friends today acknowledge us. Our strong commitment is recognised, and all criteria are met.
"Today is a great, a historic day for the Republic of Macedonia. I promise that we will bring more good news in the period ahead, in the interests of all citizens of our country. The doors towards NATO are now open."
Countries hoping to join NATO must win unanimous approval from existing members and Greece blocked Macedonia's bid 10 years ago because of the name row.
Athens insisted Macedonia should change its name because it has its own northern province of the same name, which in ancient times was the cradle of Alexander the Great's empire -- a source of intense pride for modern-day Greeks.
© 2018 AFP