Nine people, mostly civilians, were killed in an explosion on Saturday in the northwestern Syrian city of Idlib, a UK-based war monitor said.
The Syrian Observatory for Human Rights said the blast left 26 people injured, adding that the cause of the explosion remains unclear.
In recent months, a number of blasts have rocked Idlib province, which has witnessed infighting between competing hardline groups opposed to President Bashar Al Assad.
The most prominent armed group is Hayat Tahrir Al Sham, which is led by Syria's former Al Qaeda branch.
More than 350,000 people have been killed in Syria's war and millions displaced since it erupted in 2011 with a brutal crackdown on anti-government demonstrations.