IDLIB, Syria 

Syria's Bashar al-Assad regime and Iran-backed terror groups attacked a center of the White Helmets civil defense agency in northwestern Idlib on Sunday, killing a civil defense worker, according to local sources.  

The attack was carried out in Marek district, which is located inside the Idlib de-escalation zone.  

The civil defense center was heavily damaged and became unusable as a result of the attack, the sources said on condition of anonymity due to restrictions on speaking to the media.

On Saturday, a volunteer was killed when another White Helmets center was hit by a warplane, which belonged to Russia, according to the opposition.  

Regime attacks in Idlib’s de-escalation zone are estimated to have killed at least 117 civilians -- and injured more than 342 others -- since the beginning of 2019.  

In September 2018, Turkey and Russia agreed to turn Idlib into a demilitarized zone after a meeting between Turkish President Recep Tayyip Erdogan and his counterpart Vladimir Putin in Russia's coastal city of Sochi.  

Ankara and Moscow signed a memorandum of understanding calling for the stabilization of the situation in Idlib's de-escalation zone, in which acts of aggression are prohibited.   

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

* Writing by Fatih Hafiz Mehmet