US Secretary of State Rex Tillerson is in Lebanon and is set to head to Turkey on Thursday in a bid to ease tensions over Ankara's ongoing operation inside Syria.

Tillerson's two days in Turkey is part of his five-country Middle East tour. He is set to hold talks with Turkish President Recep Tayyip Erdogan and Foreign Minister Mevlut Cavusoglu. Turkey's operation against the People's Protection Units or YPG, which Ankara blacklists as a terror group, has seen troops fighting a militia which is closely allied with Washington in the battle against jihadists. Erdogan has warned US troops to steer clear of Manbij -- a YPG-held town east of Afrin where the main operation is being carried out -- raising fears of possible clashes.