“The United States cooperates with them on the issue of fighting Daesh [Islamic State]. This situation is unacceptable to us. We have repeatedly told the US side that it was impossible to destroy one terrorist organization while using another for this. This cannot be called a method of countering terrorism,” Yildirim said.
Tensions between Ankara and the Kurds escalated in July 2015 when a ceasefire between Turkey and the Kurdistan Workers’ Party (PKK) collapsed over a series of terrorist attacks, allegedly committed by PKK members. Ankara considers the Democratic Union Party (PYD), and its military wing YPG (People's Protection Units) operating in Syria an affiliate of PKK, which is outlawed in Turkey. At the same time, the PKK denies having any ties to the PYD.
The United States has been providing military assistance to the Kurdish YPG and top Pentagon officials have described the Kurdish forces as capable and successful fighters against the Daesh terror group.