The death from Sunday's car bombing in northwestern Syria has risen to 21, the White Helmets civil-defence agency said Monday, reports Anadolu Agency.
At least 45 people were also injured during the explosion, the White Helmets added.
The incident took place at a market in the opposition-held city of Azaz, near the Turkish border.
No group has yet claimed responsibility for the attack.
Since 2016, Turkey's Euphrates Shield and Olive Branch operations in northern Syria have liberated the region from the YPG/PKK and Daesh terrorists, including Al-Bab, Afrin, and Azaz, making it possible for Syrians who fled the violence there to return home.
Syria has only just begun to emerge from a devastating conflict that began in 2011 when the Bashar al-Assad regime cracked down on demonstrators with unexpected ferocity.
Hundreds of thousands of civilians have been killed or displaced in the conflict, mainly by regime airstrikes targeting opposition-held areas.