NATO Secretary General Jens Stoltenberg said on Thursday that Sweden and Finland were ready to join the military alliance.
Stoltenberg said the two Nordic states had delivered on Turkey's demands, paving the way for accession.
"It's time to welcome Finland and Sweden as members of NATO," he told a press conference alongside Turkish Foreign Minister Mevlut Cavusoglu in Istanbul.
"In these dangerous times it is even more important to finalize their accession, to prevent any misunderstanding or miscalculation in Moscow," Stoltenberg added.
Commitments to Turkey being implemented — Stoltenberg
Turkey has been the only NATO member explicitly opposed to Helsinki and Stockholm's accession, with Turkish President Recep Tayyip Erdogan accusing the countries of harboring Kurdish militants classified as "terrorists" by Ankara.
Stoltenberg said Sweden and Finland had implemented commitments made in June, including provisions on extraditions and information sharing.
Cavusoglu was a bit more guarded, saying that Stockholm had taken some steps, including removing arms sales restrictions to Turkey but said "it's not possible to say" the July agreement was fully implemented.
Cavusoglu warned that the changes must be permanent and that Sweden should not backtrack once NATO membership was secured.
"We don't intend to harm NATO or block its enlargement ... we want to see concrete steps," Cavusoglu said.
Stoltenberg was confident Finland and Sweden had done enough for the states to join the alliance.
"I recognize your concerns. At the same time, it is clear Finland and Sweden have delivered on the memorandum and are committed to the long-term partnership with Turkey,'' Stoltenberg told Cavusoglu.
There needs to be unanimous consent among all 30 NATO members for Finland and Sweden to join.
The Nordic countries both dropped decades of military non-alignment and rushed to become NATO members in May following Russia's invasion of Ukraine.
kb/sms (dpa, AFP, Reuters)