(Bloomberg) -- Turkish President Recep Tayyip Erdogan said he won’t allow Sweden and Finland to join NATO because of their stances on Kurdish militants, throwing a wrench into plans to strengthen the western military alliance after Russia’s invasion of Ukraine.

At a press conference in Ankara late Monday, Erdogan poured cold water on expectations that Turkish opposition to the enlargement plan could be easily resolved. The remarks were his clearest indication that he intends to block membership for the two countries, or at least extract concessions for it, since they announced their intentions to join over the weekend.

“These two countries lack a clear stance against terrorism” and “Sweden is a nesting ground for terrorist organizations,” Erdogan said. He also said that Turkey wouldn’t allow countries that impose “sanctions” on Turkey to join NATO, an apparent reference to restrictions on weapons sales imposed by several European nations.

At the heart of the matter is Erdogan’s deep resentment against NATO allies for what he sees as their refusal to take seriously Ankara’s concerns about Kurdish militants operating inside Turkey and across its borders in Syria and Iraq. Turkey wants its perception of the threat to be acknowledged by all NATO members, and says risk priorities should be harmonized across the alliance.

NATO Secretary General Jens Stoltenberg had said he expected to work through the last-minute wrinkle to the enlargement plan. But that looks unlikely to happen immediately, with Erdogan saying Monday that officials from Sweden and Finland planning to visit Ankara for talks shouldn’t even bother coming.

Syrian War

Much of the dispute boils down to how allied countries differentiate between two linked Kurdish groups that Turkey is fighting against. While Turkey, the US and European Union are aligned in considering the Kurdistan Workers’ Party, or PKK, a terrorist organization inside Turkey, the US and Europe have armed the group’s Syrian affiliate, the YPG. Turkey considers the YPG and PKK to be branches of the same group.

Western support for the Kurdish fighters inside Syria accelerated after Islamic State captured vast swaths of Syria and Iraq starting in 2014. The US and some European governments funneled support, including weapons, to the YPG to help roll back the jihadist gains. 

Turkey, alarmed at the prospect of a well-armed proto-Kurdish army that could aid separatist Kurdish aspirations, sent its army into Syria to push the group away from its border. Many EU countries, including Sweden and Finland, then responded with restrictions on weapons sales to Turkey.

“We’ve called on these countries, along with existing NATO members, to stop supporting these terrorists and end the practice of restricting arms exports to Turkey since it is against the spirit of the alliance,” Turkey’s Foreign Minister Mevlut Cavusoglu said in Berlin on Sunday at a meeting of the alliance. 

Earlier Monday, Turkey’s state news agency Anadolu laid out a detailed account of Turkey’s specific complaints about Sweden and Finland’s alleged support for Kurdish militants.

It reported that Swedish-made AT-4 anti-tank weapons were used by the YPG in attacks on Turkish forces in Syria, without claiming that Sweden provided the munitions that are in the arsenals of several militaries around the world. It also highlighted alleged contacts between senior Swedish and Kurdish officials. 

Turning to Finland, Anadolu cited what it said was Helsinki’s opposition to Turkish cross-border military operations against Kurdish militants, and a 2019 decision not to approve any new defense export licenses to Turkey, the year EU foreign ministers together pledged to restrict arms sales to Turkey over its military operation in Syria.

A senior Turkish official confirmed that the Anadolu report reflects Ankara’s concerns.

Why U.S. and Turkey Disagree About Syrian Kurds: QuickTake Q&A

On Monday, Finland’s foreign minister reiterated his surprise at the late Turkish intervention in his country’s application.

Speaking in parliament in Helsinki, Pekka Haavisto said Cavusoglu had informed him on May 5 that the Finnish accession into NATO would be a “very straightforward process in Turkey,” and that President Sauli Niinisto had been relayed a similar message by Erdogan.

“Since then, these additional questions have arisen, relating to PKK,” Haavisto said. “We have a clear answer. We’re not bargaining, we respond: PKK is banned in Finland, because it’s also on the EU list of terrorist organizations.” 

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