Progress on Finland and Sweden’s Nato membership bids will only be possible if concrete steps are taken to address Turkey’s national security concerns, President Tayyip Erdogan’s spokesman has said.

Ibrahim Kalin, who is Erdogan’s chief foreign policy adviser, held calls on Wednesday with counterparts from Sweden, Finland, Germany, the UK and the United States to discuss the proposed NATO enlargement, according to a readout from Erdogan’s office, reported on by Reuters.

“It was underlined that if Turkey’s expectations were not met, the progress of the process would not be possible,” it said.

Also on Wednesday, Turkish foreign minister Mevlut Cavusoglu met US Secretary of State Antony Blinken in New York to discuss Turkey’s objections.

After the meeting Cavusoglu said Blinken had assured him the necessary messages regarding Turkey’s security concerns over Sweden and Finland’s membership would be passed on.

Turkey accuses the two Nordic nations of harbouring members of the Kurdistan Workers’ Party (PKK), a group it views as a terrorist organisation, and followers of Fethullah Gulen, who Ankara accuses of orchestrating a 2016 coup attempt.

Without the support of all Nato members, Sweden and Finland cannot join the military alliance.