Three civilians, including a child, were killed in a car-bomb attack in Syria’s northwestern Idlib province on Sunday, according to the White Helmets civil defense agency.
Thirteen other people were injured in the bombing that took place in the center of Idlib, it added.
Several buildings and vehicles sustained damage in the attack.
Located in northwestern Syria near the Turkish border, Idlib was declared a "de-escalation zone" last May, in which acts of aggression are expressly forbidden.
Syria has only just begun to emerge from a devastating conflict that began in 2011 when the Assad regime cracked down on demonstrators with unexpected ferocity.
UN officials say hundreds of thousands of people have been killed in the conflict.