During the closed-door meeting at the presidential complex, Erdogan and Tillerson addressed ongoing efforts to clear Daesh from Syria and Iraq as well as the extradition of Fetullah Gulen, the U.S.- based ringleader of the Fetullah Terrorist Organization (FETO), according to the source who spoke on condition of anonymity due to restrictions on talking to the media.

Erdogan reiterated Ankara's request to have Gulen extradited from the U.S. in the aftermath of the July 15 coup attempt which Ankara accuses Gulen of orchestrating. Last year's coup bid left 249 people martyred, and nearly 2,200 others injured.

During the meeting, Turkish president also underlined the importance of working with "legitimate" actors in fighting terrorism.

Although the PKK is listed as a terrorist organization by Turkey, the U.S. and EU, the U.S. considers PKK's Syrian offshoot PYD, and its armed wing YPG "reliable partners" in the region in the fight against Daesh. Neither the EU nor the U.S. regard PYD or YPG as its offshoots.

Earlier on Thursday, Tillerson met Prime Minister Binali Yildirim, and the two discussed the ongoing fight against Daesh, as well as Gulen's extradition.

The U.S. secretary of state is scheduled to visit NATO in Brussels on Friday.

Anadolu Agency