Turkey wants Sweden to begin extraditing or expelling suspected Kurdish separatists before next month’s summit of the North Atlantic Treaty Organization to help win its support to join the security alliance, according to people familiar with the matter.

Sweden, along with neighboring Finland, sought to become NATO members after Russia’s invasion of Ukraine in 2022. Finland joined in April but Turkey blocked Sweden’s accession, accusing it of offering refuge to political activists wanted on terrorism charges.

Read More: Turkey Digs In on Sweden’s NATO Bid as Allies Mount Pressure

Sweden lifted a ban on arms sales to Turkey and amended its anti-terrorism laws as part of a deal clinched last year to break the impasse. President Recep Tayyip Erdogan signaled last week, however, that those steps may not be enough to win Turkish support for the bid at the next NATO summit in the Lithuanian capital of Vilnius.

As far as Ankara is concerned, there is more room for progress in Sweden’s “curtailing activities of groups” deemed terrorist by Turkey, according to Alper Coskun, a senior fellow at the Carnegie Endowment for International Peace.

“Turkey has an interest in ensuring that Sweden joins the alliance, but it has continuing expectations from Sweden,” Coskun, a former Turkish diplomat, told an Atlantic Council conference on Thursday. “Because of the fact that Turkey has an interest in Sweden joining NATO, I think that the path is open for a positive expectation.”

Turkey wants Sweden to begin extraditing or expelling suspects to prove it’s serious about implementing the new rules, said the people, speaking on condition of anonymity to share sensitive information. Turkey has demanded the extradition of more than 130 individuals, most of them Kurdish separatists.

They include alleged supporters of Kurdish militant group the PKK, which is labeled a terrorist organization by the US and the European Union, as well as of affiliated Kurdish YPG forces in Syria and followers of US-based cleric Fethullah Gulen. Erdogan alleges Gulen masterminded a 2016 coup attempt in Turkey.

Turkey’s government didn’t respond to a request for comment. The Swedish foreign minister’s office declined to comment.

Extradition requests to Sweden are handled by the country’s judiciary. The government can’t overrule decisions by its Supreme Court, which has rejected appeals from Turkey on various grounds, including risk of persecution.

NATO allies have repeatedly urged Turkey to approve Sweden’s bid in time for the Vilnius summit, saying the country meets all qualifications. The latest call came from German Chancellor Olaf Scholz on Thursday.

“I firmly believe that Sweden should join Finland at the summit table as a new ally,” Scholz told the parliament in Berlin. “And I appeal to Turkey’s re-elected President Erdogan to now clear the way for this - as we all decided together in Madrid last year.”

Sweden’s accession would clinch NATO’s control of the Baltic Sea and give the alliance the upper hand in the Arctic region — both strategic gateways for Russia — even as Moscow is bogged down in its invasion of Ukraine.

Finland completed the process to join the alliance in April, leaving Sweden in limbo over its prospects, with both Turkey and Hungary’s ratifications outstanding.

--With assistance from Michael Nienaber and Niclas Rolander.

(Updates with analyst comments starting in fourth paragraph.)