After talks in Vilnius with Erdogan and Sweden's Prime Minister Ulf Kristersson, Stoltenberg said Turkey had agreed to move forward, declaring: "This is a historic day."

"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," he said.

A separate joint statement was issued, outlining the agreement between Sweden and Turkey.

Turkey has been holding up Sweden's application to join the Atlantic alliance, accusing Stockholm of harbouring Kurdish activists Ankara regards as terrorists.

And on Monday, Erdogan upped the stakes further, demanding that the European Union revive Turkey's stalled EU membership bid as a precondition for Sweden joining NATO.

But the statement issued after the three-way talks stated that Turkey and Sweden would work closely in "counter-terrorism coordination" and also boost bilateral trade ties.

"Sweden will actively support efforts to reinvigorate Turkiye's EU accession process, including modernisation of the EU-Turkiye Customs Union and visa liberalisation," the statement said.

US President Joe Biden welcomed Erdogan's agreement to support Sweden's application to join NATO.

"I stand ready to work with President Erdogan and Turkey on enhancing defense and deterrence in the Euro-Atlantic area," Biden said in a statement, adding: "I look forward to welcoming Prime Minister Kristersson and Sweden as our 32nd NATO ally."