Following the NATO row on account of Ankara accusing Sweden and Finland of supporting the PKK, which Turkey has listed as a terrorist organization, Turkish President Recep Tayyip Erdogan's top foreign policy advisor said on Monday that Ankara does not view the NATO summit, which is set to take place next week, as the final deadline to resolve objections to Finland and Sweden joining the alliance.

The comments from Erdogan's Advisor, Ibrahim Kalin, followed talks between Turkey, Sweden and Finland, which NATO leaders had hoped would pave the way for a formal approval for the Nordic states to join the alliance.

But with Ankara accusing them both of providing a safe haven for PKK militants, which Turkey has been fighting against for decades, demanding the two countries lift their weapons freezes on Turkey, and them not reaching a deal with Ankara, the talks yielded no significant results.

"The Madrid NATO summit is not the deadline, so our negotiations will continue," Kalin told reporters, adding that "the existence of terrorist organizations must end in those countries. That is what we expect both from Finland and Sweden." 

"Turkey's has legitimate security concerns over terrorism that we need to address," NATO Secretary-General Jens Stoltenberg said.  

"So we will continue our talks on Finland and Sweden's applications for NATO membership, and I look forward to finding a way forward as soon as possible."