"We have never given heavy arms to the YPG so there is none to take back," Tillerson said in response to a question at a press conference in the Lebanese capital Beirut before heading for Ankara.

Turkey has repeatedly accused the United States of massively arming the YPG, and has said Washington must gather up its weapons now that the peak of the fight against jihadists has passed.

Turkey's President Recep Tayyip Erdogan earlier this month accused Washington of sending in 5,000 truckloads of weapons to the YPG in Syria, as well as 2,000 planeloads of arms.

"The United States says 'we have cleansed (the area) of Daesh'," Erdogan said, using an Arabic acronym for the group.

"So if you have cleansed it from Daesh then why are you still here?" he asked.

Last month, Turkey launched an offensive against the Kurdish enclave of Afrin in northwest Syria aimed at ousting the YPG fighters from the border area.

The cross-border campaign involves both ground troops and air strikes in support of Syrian rebels against the YPG.

Syria's Kurds, estimated at 15 percent of the population, were oppressed for decades under the regime of the President Bashar al-Assad and his late father Hafez.

But they took advantage of the civil war unleashed in Syria in 2011 to establish de facto autonomy in territory they control in the north and northeast.

During his two-day trip to Turkey, Tillerson will hold talks with his Turkish counterpart Mevlut Cavusoglu and with Erdogan.