(Bloomberg) -- Officials heading to the NATO summit in Madrid are holding out hope of persuading Turkey to allow Finland and Sweden to advance their membership applications. 

US President Joe Biden told his Turkish counterpart, Recep Tayyip Erdogan, he’s looking forward to speaking to him in the Spanish capital in a phone call on Tuesday morning, the White House said. Erdogan is also due to hold talks with Finnish President Sauli Niinisto and Sweden’s Magdalena Andersson on Tuesday afternoon. 

Erdogan’s government, which has the power to veto the accession of the two Nordic countries, has stalled their bids, saying they aren’t doing enough to tackle Kurdish groups that Turkey views as terrorists. Erdogan has also called for restrictions on weapons sales to be lifted.

“I’m neither optimistic nor pessimistic,” Niinisto told reporters in Madrid. “The general view appears to be the talks went better, which would seem to mean somewhat more understanding on both sides.”

If their applications are successful, the move to include two previously neutral countries in the military alliance would mark a significant shift in the European security landscape after Russia’s war against Ukraine.

Erdogan is expected to take a tough stand in Madrid, especially toward Sweden, according to a Turkish official. Another Turkish official saw no progress but an attempt to create a positive atmosphere, with the issue riding on a political decision by Erdogan.

“If they are going to become members, then they have to take Turkey’s security concerns seriously,” Erdogan told reporters Tuesday before flying to Madrid. “We’ll have the four-way conversation and see where they come from. We don’t want dry words, we want results.”

Erdogan said Biden had expressed his intention to meet, and that an encounter was likely later Tuesday, or Wednesday.

Tough Stand

NATO Secretary General Jens Stoltenberg has held talks with Erdogan over recent days. Officials from Turkey, Finland and Sweden also met separately in recent days.

A membership process would make many months, including ratification from NATO allies’ parliaments, before the applicants become members and can benefit from the alliance’s article 5 collective defense commitments.

The US has stressed that bringing the two Nordic countries into the fold could make the alliance more secure. Turkey’s block in recent weeks also complicated the allies’ efforts to present a united front in light of Russia’s aggression in Ukraine.  

Read More: NATO Expansion Could Finally Shore Up Alliance’s Weakest Flank

Sweden has tightened laws on terrorism in recent years, and more steps in that direction are under way. Niinisto has said Finland’s anti-terror legislation is on par with current NATO members following a revamp last year.

The Nordic nations have also highlighted constitutional protections for freedom of speech, meaning they could not prevent peaceful Kurdish demonstrations, and said any extraditions requested by Turkey must be ruled on by courts. When it comes to lifting bans on arms exports, Andersson in June signaled that the Swedish authorities that grant arms-export approvals may take a different view on shipments to Turkey in light of the NATO membership bid.

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