Turkish President Recep Tayyip Erdogan claims he has proof the U.S. and its allies gave material support to the Islamic State, but his contention repeated most loudly and insistently is that America armed the Kurdish militia in Syria, which Turkey considers an offshoot of the Kurdish separatists it has been battling for decades.

The Associated Press reports on the latest accusations from Ankara:

Foreign Minister Mevlut Cavusoglu said Thursday: “The United States has provided arms to the YPG — period.”

He was responding to a U.S. Embassy statement a day earlier which said the U.S. had not “provided weapons or explosives to the YPG or the PKK — period.”

Turkey views the U.S.-backed People’s Protection Units, or YPG, as a terrorist organization because of its links to Turkey’s outlawed Kurdistan Workers’ Party, or PKK.

President Recep Tayyip Erdogan also rebuffed the U.S. denials and called on Washington to side with its ally.

Erdogan said: “Aren’t we partners in NATO? Why are you supporting a terror organization and not us?”

Reuters has more from Erdogan’s speech on Thursday: “We, as Turkey, have been calling on Western nations for some time to not distinguish between terrorist organizations and to be principled and consistent in their stance. Some countries, namely the United States, have come up with some excuses on their own and overtly supported the organisations that massacre innocent people in our region.”

The YPG was reportedly not included in the ceasefire deal announced by Russia and Turkey on Thursday.

Voice of America notes that Cavusoglu also complained about the U.S.-led coalition in Syria failing to provide air cover for Turkish troops and Turkish-supported militia and claimed it was because “the YPG is exerting pressure on America.”

Erdogan echoed this complaint as well: “We are with you in NATO but despite this, you give support to separatist terror organizations and not to us. This is not something we can accept… In our operation in al-Bab, we are not seeing the slightest support from NATO or from our allies who have forces in the region.”

Al-Bab is a town in Syria where Turkey and allied local forces have been fighting the Islamic State. The next city on Turkey’s declared mission plan is Manbij, which is currently held by the Kurds and not ISIS.