Three children were killed when regime forces shelled opposition-held areas in Hama province in west-central Syria on Saturday, according to the White Helmets civil defense agency.
Two other children were seriously injured in the shelling that targeted the towns of Kafr Zita, Latamne and Lahaya in the province, the agency said.
Hama falls within de-escalation zones defined last year in Astana peace talks.
According to White Helmets, at least 13 civilians were killed and dozens injured in regime attacks in Hama and Idlib provinces over the past week.
Syria has remained locked in a vicious conflict since 2011 when the Bashar al-Assad regime cracked down on demonstrators with unexpected ferocity. Since then, hundreds of thousands of people have been killed in the conflict and millions more rendered homeless, according to UN figures.