At least 11 people including four children were killed Thursday in air strikes on rebel-held areas near the Syrian capital, a monitor said.

One strike on the besieged town of Douma killed eight people including three children, according to the Syrian Observatory for Human Rights.

A separate strike on nearby Sabqa killed two women and a young girl, it said.

The raids are part of a six-month offensive by government forces that has chipped away at rebel-held villages and farmland across Eastern Ghouta, according to the Observatory.

Douma, the largest town in the Eastern Ghouta area with more than 100,000 residents, is surrounded and regularly shelled by regime forces.

Syria's five-year conflict has left more than 300,000 people dead.