Turkey regularly called on the administration of former US President Barack Obama to provide more support for Turkey's position in the fight against regional terror, including the struggle against Daesh in Syria and Iraq.
Turkey and the US are also at odds over US support for the YPG, the armed wing of the PYD, a Syrian affiliate of the PKK, which Turkey, the US and EU list as a terrorist organisation.
US President Donald Trump has promised more coordination with Turkey, a NATO member, on the issue of fighting terror. Whether that extends to US support for the YPG could become clearer on Friday with the visit to Ankara by the Chairman of the US Joint Chiefs of Staff.
General Joseph Dunford was appointed chairman of the joint chiefs in September 2015, by then President Barack Obama.
Dunford's visit to Ankara follows one a week ago by new CIA Director Mike Pompeo.
TRT World’s Francis Collings has this preview of Dunford's visit.