NATO Secretary-General Jens Stoltenberg (C), Turkish President Tayyip Erdogan (L) and Swedish Prime Minister Ulf Kristersson at a meeting on the eve of a NATO summit, in Vilnius, Lithuania, July 10, 2023. (Photo: The Guardian)

Sweden and Finland applied for NATO membership last year. While Finland's NATO membership was green-lighted in April, Turkey and Hungary have yet to clear Sweden's bid.

Stockholm has been working to join the bloc at the alliance's summit in the Lithuanian capital Vilnius, which began on Tuesday.

“President Erdogan has agreed to forward the accession protocol for Sweden to the grand national assembly as soon as possible, and work closely with the assembly to ensure ratification," NATO Secretary General Jens Stoltenberg told a news conference, describing it as a "historic" step.

Stoltenberg convened Erdogan and Swedish Prime Minister Ulf Kristersson for several hours of talks on the eve of the summit as he sought to finally break the deadlock.

Turkey has accused Sweden of not doing enough against people Turkey sees as terrorists, mainly members of the outlawed Kurdistan Workers Party (PKK) that is considered a terrorist organisation by Turkey, the EU and the United States.