According to a statement by Turkish presidency's communication office on Aug. 23, Erdogan said the Syrian attack on Idlib damage efforts to find a solution to Syria crisis and pose a serious threat to Turkey's national security.

Turkey and Russia agreed last September to turn Idlib into a de-escalation zone where acts of aggression are expressly prohibited.

The de-escalation zone is currently home to some 4 million civilians, including hundreds of thousands displaced in recent years by regime forces from throughout the war-weary country.

Syria has been locked in a vicious civil war since early 2011.

Syria has always reprimanded Turkey for interfering in Syria affairs and sending forces into the country without asking for permission from Damascus.

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