Turkish President Recep Tayyip Erdoğan is due to meet Swedish Prime Minister Magdalena Andersson and Finnish President Sauli Niinistö in Madrid on Tuesday to discuss the stalled Swedish and Finnish bids to join the NATO alliance.
Erdoğan, who is currently blocking both bids, has accused the two countries of supporting terrorist groups that are banned in Turkey and showed no readiness to compromise on Turkey's position ahead of the talks.
"Tomorrow we will go to the NATO summit in Spain and do everything necessary in accordance with the rights and interests of our country," Erdoğan said on Monday, according to government sources.
He said the "hypocrisy" concerning "terrorist organizations" would be explained to his fellow NATO leaders with "documents, information and pictures."
Erdoğan charges Sweden and Finland with backing the Kurdistan Workers' Party (PKK) and the YPG, a Kurdish militia based in Syria, both of which Ankara classifies as terrorist groups. Sweden and Finland both dispute the Turkish accusations, however.
New strategic outlook
NATO Secretary Jens Stoltenberg will also attend the talks in the hopes of avoiding Turkish opposition to the Swedish and Finnish membership bids from overshadowing the first day of the NATO summit.
Leaders of the 30-strong defence alliance are meeting in the Spanish capital to adopt a new strategic outlook and to agree plans for the reinforcement of NATO's eastern flank in light of Russia's invasion of Ukraine.