France has obtained "accurate information" that Syrian militants from Turkey are taking part in hostilities in Nagorno-Karabakh, French President Emmanuel Macron said upon arriving at a key EU summit in Brussels on Thursday, October 1.

"We have accurate information that shows that Syrian militants have left the battlefield in Gaziantep (a province in southern Turkey - Ed.) to join fighting in Karabakh," TASS cited Macron as saying.

"This is very serious. In the coming hours, we will discuss [the matter] at the summit."

Armenia was the first to report on Turkey's deployment of thousands of Syrian fighters to Azerbaijan on September 28. International media publications followed suit, as did reaction from the U.S., France and Russia.

Azerbaijan launched a major offensive against Karabakh (Artsakh) in the morning of September 27, shelling Armenian positions and civilian settlements with large caliber weapons and rocket systems. Armenia and Karabakh have introduced martial law and total mobilization. The Armenian side has reported deaths and injuries both among the civilian population and the military. On September 29, the Azerbaijani army began shelling positions and civilian settlements in Armenia, which resulted in civilian casualty. On October 1, a group of local and international journalists came under Azerbaijan's shelling of civilian settlements. Some of them have sustained injuries.