A prominent Syrian activist group monitoring its civil war says U.S.-led airstrikes in the country have killed over 900 people since September, many fighters of the militant Islamic State in Iraq and Syria group, though some civilians as well.

The Britain-based Syrian Observatory for Human Rights said Saturday that the U.S.-led airstrikes have killed 785 ISIS militants. It said the strikes also have killed 72 militants of Syria's al7-Qaeda's affiliate, the Nusra Front.

The Observatory, which observers believe provides the conflict's most accurate death tolls, said the U.S.-led strikes also killed 52 civilians, including eight women and five children.

A U.S.-led coalition began striking ISIS in late September in Syria after targeting the group in Iraq.

Activists say Syria's civil war has killed over 200,000 people.