US never gave 'heavy arms' to Kurdish YPG in Syria: Tillerson

US Secretary of State Rex Tillerson said on Thursday that Washington has never supplied heavy weaponry in Syria to the Kurdish People's Protection Units (YPG), which Ankara blacklists as a terror group.

"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 Beirut before heading for Ankara.

In Turkey, Tillerson and Turkey's President Recep Tayyip Erdogan had a "productive and open" talk on Thursday about improving ties strained recently over their policies on Syria, in a meeting following weeks of escalating anti-American rhetoric from Ankara.

Tillerson arrived in Turkey on Thursday for two days of what officials have said would likely be uncomfortable discussions between the allies, whose relations have frayed over a number of issues, particularly U.S. support for the Syrian Kurdish YPG militia, seen as terrorists by Turkey.

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

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?" 

Tillerson is currently on a five-nation tour of the Middle East, a week after major flashpoints in neighbouring Syria including the killing of at least 100 pro-government forces by the US-led coalition in Deir Ezzor and the downing of an Israeli F-16 by Syrian aircraft fire. 

Hezbollah threat

During an earlier news conference alongside Lebanese Prime Minister Saad al-Hariri, Tillerson said that Lebanon's security was threatened by the growing arsenal of Hezbollah and the group's involvement in regional conflicts.

Hezbollah, which is designated as a terrorist organisation by the US, is part of Hariri's government. Its military strength has grown since the last major conflict with Israel in 2006.

Tensions between the states have spiked recently because of Israeli plans to build a wall at the border, and because of Lebanon's decision to begin exploring for oil and gas in an offshore block in disputed waters.

Tillerson urged Lebanese leaders to uphold the country's commitment to staying out of regional conflicts, a reference to Hezbollah's role in wars around the region including in Syria where Iran also holds major sway.

Lebanon is a big recipient of US military support. Tillerson said Washington remained committed to supporting the Lebanese army and internal security forces.

The United States has been mediating between Lebanon and Israel over their border dispute. In apparent reference to the maritime dispute, Tillerson said: "We've asked no one to give up anything."

Tillerson left Beirut for a two-day trip to Turkey where he is scheduled to hold talks with his Turkish counterpart Mevlut Cavusoglu and with Erdogan.