Turkey has hit out at the US over images said to show US special forces in Syria wearing insignia of Kurdish militia, during joint operations against so-called Islamic State (IS).
Turkish Foreign Minister Mevlut Cavusoglu called the US "two-faced" and said the practice was "unacceptable".
The images appear to show a US special forces soldier wearing the patch of the YPG, a Kurdish militia group.
On Friday the US ordered its personnel to remove the patches.
A US spokesman in Baghdad, Col Steve Warren, said the wearing of the patches was unauthorised, and admitted there were political sensitivities on this occasion which made the practice inappropriate.
Turkish authorities accuse the YPG of being linked to the banned PKK Kurdish militant group, which the Turks, along with the EU and US, regard as a terrorist organisation.
The Pentagon had initially said troops wore the insignia to blend in.