ANKARA 

Assad regime's ceasefire violations in Idlib, northwestern Syria, is causing a “major humanitarian crisis,” Turkish president told his Russian counterpart over phone.

According to a statement by Turkish presidency’s communication office on Friday, Recep Tayyip Erdogan and Vladimir Putin discussed the latest developments in war-weary Syria and Libya.

During the phone conversation, Erdogan said the regime’s attacks in Idlib -- an area where a cease-fire is supposed to be in effect -- 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 Syrian regime and its allies, however, have consistently broken the terms of the cease-fire, launching frequent attacks inside the zone.

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, when the Bashar al-Assad regime cracked down on pro-democracy protests with unexpected ferocity.

Since then, hundreds of thousands of people have been killed and more than 10 million others displaced, according to UN officials.