Turkish President Recep Tayyip Erdogan on Thursday said he would meet his US counterpart Donald Trump in Washington on May 16-17, in their first meeting since Trump took office in January.
Ties between the United States and Turkey have deteriorated since a failed military coup in July 2016 and disagreements over US support for the YPG in Syria.
The YPG is the dominant group within the US-backed Syrian Democratic Forces (SDF) in Syria. It is also the armed wing of the PYD, a Syrian affiliate of the PKK, which Turkey, the US and EU list as a terrorist organisation.
The PKK launched an armed insurgency in Turkey in 1984.
Ankara is also pressing for the extradition of US-based Fethullah Gulen, whom Turkey accuses of engineering the July 15, 2016 failed coup and of being behind a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary.
"This terrorist leader is residing in a country which is our strategic ally, and it is upsetting not only me but also the Turkish nation," Erdogan said on Thursday. "I think they will at least call him to account."
Erdogan added that he sees prospects for an improvement in ties with its NATO ally under Trump. The two leaders have talked on the telephone three times since Trump took office, including a call on Monday after Erdogan won a referendum on constitutional change, shifting Turkey's system of governance from a parliamentary system to presidential one.