Syria's White Helmets say at least six people were killed and 10 remain under rubble following government air raids on a town in the rebel's last stronghold.

The first responders known as White Helmets said Monday that rescue workers were still searching for survivors under the rubble after the airstrikes hit a crowded residential street in the town of Ariha. They said five women and a child were killed.

The airstrikes hit the town amid intense government bombardment in Idlib province and its environs.

The Syrian Observatory for Human Rights says there were more than 100 air raids and as many as 93 barrel bombs dropped Monday on the southern section of the rebel stronghold.

The violence has displaced more than 200,000 people since erupting in late April.