Turkey has called for the removal of the US diplomat coordinating an international coalition fighting the Islamic State in Iraq and the Levant (ISIL, also known as ISIS) group in Syria and Iraq, accusing him of backing Syrian Kurdish fighters.
Ankara regards the Kurdish Peoples' Protection Units (YPG) as an extension of the Kurdistan Workers Party (PKK) group, which has been fighting a decades-old armed campaign in southeast Turkey and is considered a "terrorist organisation" by Turkey, the United States and the European Union.
Yet the US views the YPG, a central part of the Syrian Democratic Forces (SDF), as its main ally in the battle on the ground against ISIL. Earlier in May, US President Donald Trump pledged to arm the group ahead of a planned attack on Raqqa, ISIL's self-proclaimed capital in Syria.