The rest of the dead in the raids on the city of Raqqa were ISIS fighters, the Syrian Observatory for Human Rights said.

The US-led coalition, which launched an air war against ISIS in Syria last September, said it had carried out "significant" air strikes against Raqa.

Coalition forces "successfully engaged multiple targets" throughout Raqqa, the statement said, destroying ISIS structures and transit routes.

The strikes "have severely constricted terrorist freedom of movement," it added.

He had no indication about civilian casualty in 2 days attacks.

Washington is leading a coalition fighting ISIS in Syria and Iraq, where the extremist group has proclaimed an "Islamic caliphate" in territory under its control.The group emerged in Syria in 2013.