At least 20 people were killed on Monday when a car bomb exploded in the Syrian town of Darkush in northwestern Idlib province, near the Turkish border, an NGO said.
The Syrian Observatory for Human Rights said the toll was expected to rise due to the large number of people who suffered serious injuries, and that at least one child was among the dead.
Activists from the Syrian Revolution General Commission network said the blast took place in the market area of the Darkush, which is under rebel control.
A video posted by activists online showed the aftermath of the blast, with at least one car ablaze and the ground around it covering in smoking embers.
A second video showed residents carrying bodies on makeshift stretchers and extensive damage to buildings around the blast site.
Darkush, which lies on the Orontes river, is just a few kilometres from the border with Turkey.