The Turkish President argued Finland's plan to apply for NATO membership, and the expectation that Sweden will follow, would bring about the expansion of the alliance that Russian President Vladimir Putin aimed to prevent from happening by invading Ukraine. Opposition by seemingly neutral Turkey, which had acted as a venue for Russia-Ukraine peace talks, follows warnings of retaliation by Moscow, with the foreign ministry stating the Kremlin "will be forced to take retaliatory steps, both of a military-technical and other nature" if the Nordic NATO plans materialise.
President Erdoğan told reporters in Istanbul: "We are following the developments regarding Sweden and Finland, but we don't hold positive views."
Saying it was a mistake for NATO to accept Greece as a member in the past, he added: "As Turkey, we don't want to repeat similar mistakes."
Significantly ramping up the tone of his stance, Mr Erdoğan then said: Furthermore, Scandinavian countries are guesthouses for terrorist organisations.
"They are even members of the parliament in some countries.
"It is not possible for us to be in favour."
Mr Erdoğan’s comments were primarily directed at the militant group the Kurdistan Workers Party (PKK), which Turkey regards as a terrorist organisation, although they appeared to encompass the communities of Kurdish origin in Scandinavia as a whole.
Sweden has a large Kurdish diaspora, with the community considered to be one of the largest outside of the Middle East.
Prominent Swedish citizens of Kurdish origin currently include six members of parliament but Turkish authorities are yet to provide any evidence for their claims that the parliamentarians in question have links with the PKK or similar groups outside Sweden.
In Finland, the Kurdish-speaking population was estimated at just over 15,000 people as of 2020 – less than one percent of the population.
Turkey has been officially supportive of enlargement since it joined NATO seventy years ago.
NATO states that membership is open to any "European state in a position to further the principles of this Treaty and to contribute to the security of the North Atlantic area".
However, as any decision on enlargement must be made by unanimous agreement of its members, a single country opposing a nation's bid to join could block the membership from unfolding.