French President Emmanuel Macron, speaking at a European Union summit in Brussels, has demanded that Turkey explain why it has transferred Syrian Islamist militants through Turkey into the Nagorno Karabakh (NK) conflict zone bordering Azerbaijan.

Macron stated that France has confirmed the transfer and added that the Russians also have this information. He said that at least 300 ISIS fighters from the Aleppo region of Syria have been transported into the conflict zone between Azerbaijan and Armenia. The Islamic militants are fighting on the side of the Azerbaijanis. 

“I can announce that more than 300 Syrian Islamist militants, who had earlier left the Aleppo region, have been transferred to the Nagorno Karabakh conflict zone through the Turkish Gaziantep. This is a confirmed fact, these people are identified, all of them are affiliated with the Islamic State terrorist organization. I have discussed this issue with Russian President Vladimir Putin, who confirmed that Russia also possesses this information,” Macron told reporters.

“These fighters are known, tracked and identified,” Macron said, adding that he would call Turkey’s President Recep Tayyip Erdogan “in the coming days.” 

France’s response is to ask Turkey for an explanation on this point.”

“A red line has been crossed, which is unacceptable,” Macron added. “I urge all NATO partners to face up to the behavior of a NATO member.

Macron added that France is closely working with Russia and the U.S. the other co-chairs of the OSCE (Organization for Security and Cooperation in Europe), Minsk Group in seeking a peaceful solution to the NK situation.

Macron’s statements were confirmed by the Syrian civil war watchdog, the U.K.-based Syrian Observatory for Human Rights (SOHR).