On Monday, three civilians were killed in an airstrike on a Turkish military convoy moving south toward the ninth observation point, Turkey's Defense Ministry said.
The phone call came after the Syrian government allegedly attacked a Turkish military convoy in Syria's Idlib province.
Turkey and Russia agreed last September to turn Idlib into a de-escalation zone that prohibited acts of aggression.
ANKARA, Aug. 23 (Xinhua) -- Turkish President Recep Tayyip Erdogan had a phone conversation with his Russian counterpart Vladimir Putin on Friday over bilateral relations and developments in Syria and Libya.
Turkey established 12 observations points around Idlib under the framework of this deal, aiming to maintain the ceasefire between the Syrian government and rebels.
Erdogan told Putin that the Syrian government's violations of the cease-fire deal and attacks caused a major humanitarian crisis in Idlib, damaged the efforts to reach a solution to Syria crisis and turned to a serious threat to Turkey's national security, said a statement by Turkish presidency.
Turkey's ninth observation post is surrounded by the forces of Syrian President Bashar Al-Assad after they took control of the key town of Khan Sheikhoun in northwestern Syria.
The deal, however, has largely failed despite several attempts to revive it.