Turkey called Thursday for the removal of the US diplomat coordinating the international coalition fighting the Islamic State group in Iraq and Syria, accusing him of backing Syrian Kurdish militia.

Washington and Ankara are bitterly at odds over US support for the Kurdish People's Protection Units (YPG) in Syria, a group that Turkey considers a front for banned Kurdistan Workers' Party (PKK) separatists.

‘Brett McGurk is definitely giving support to PKK and YPG. It would be useful if this person was replaced,’ Foreign Minister Mevlut Cavusoglu told the private NTV television.

Last year, McGurk visited YPG members controlling the Syrian town of Kobane and was awarded a plaque, which drew Turkey's wrath.

President Recep Tayyip Erdogan angrily told Washington at the time to choose between Ankara and ‘terrorists’ there.

But Ankara is now hopeful about the future of the relationship with Washington under Donald Trump after ties frayed in the final years of Barack Obama's administration.

Erdogan on Tuesday met Trump at the White House and the two leaders promised to strengthen strained ties between the NATO allies despite the Turkish leader's stern warning about Washington's arming of a Kurdish militia.

‘It is absolutely unacceptable to take the YPG-PYD into consideration as partners in the region, and it's going against a global agreement we reached,’ Erdogan said in Washington.

The United States sees YPG as the most effective force on the ground in the fight against IS group.