"I find it useful to evaluate the NATO issue. As you know...Sweden, Finland, these countries host terrorist centres in their own countries," the Turkish president said, pointing specifically to the alleged presence of the PKK and the YPG - the Turkish and Syrian Kurdish political parties and militia groups which Ankara classify as terrorist groups, in the Nordic nations.
"NATO is a security organisation. We cannot accept the presence of terrorist organisations in it", Erdogan said, speaking to students at the presidential library in Ankara on Thursday.
Characterising Sweden as a "nest of terrorists", Erdogan stressed that "NATO requires complete unanimity of opinion, and if a country says 'no', they cannot join NATO".
"These are the countries that encourage sources of terrorism in my country, that provide them with serious financial and arms support", Erdogan said.
The Turkish president also commented on other matters, including the crisis in Ukraine and Turkey's reliance on Russian energy.
"We have ties with both sides [Russia and Ukraine]. We have the Akkuyu Nuclear Power Plant project with Russia. We will complete this project and open it next year. This is a very serious source of energy for us. We get 50 percent of the gas we consume from Russia. This is a strategic issue - strategic relations. We cannot abandon or break them", he said.
Erdogan said he would continue his "telephone diplomacy" with both President Vladimir Putin of Russia and President Volodymyr Zelensky of Ukraine, and that he has "no intention of breaking off relations" with either leader. "We will continue our policy; a new world war benefits no one", he said.
NATO Membership Row
Erdogan and other Turkish officials have spent the past week threatening to block Sweden and Finland's NATO bid or keep them permanently in the alliance's "waiting room", citing their suspected support for Kurdish autonomy- and independence-seeking forces. Political talking heads in Washington have grown livid over the idea, with some suggesting that Ankara be kicked out of the alliance for its insolence.
Turkey isn't the only country in the 30-member military bloc to have threatened to drag out the Nordics' accession. On Wednesday, Croatian President Zoran Milanovic promised to instruct Zagreb's permanent representative to NATO to vote against Finland and Sweden's admission to the North Atlantic Alliance until a dispute with neighbouring Bosnia regarding ethnic Croats' voting rights has been resolved. However, Croatia's foreign minister slammed Milanovic, accusing him of "ruining" Croatia's image in the West, and calling his proposal "blackmail".
Sweden and Finland formally submitted their NATO membership applications on Wednesday. The two countries' governments began deliberations on the matter after Russia kicked off its military operation in Ukraine in February. Both countries rejected holding a referendum on the matter.
The Nordic nations' membership in the bloc would essentially turn the Baltic Sea into a giant NATO-controlled lake, limiting the freedom of movement of the Russian Baltic Fleet and adding to the dangers posed by the alliance to the Russian exclave of Kaliningrad. Russian Deputy Foreign Minister Sergei Ryabkov warned Monday that NATO membership for the Nordics would be a "mistake with far-reaching implications", increasing military tensions and reducing stability in Northern Europe.