Story highlights Monitoring group says airstrikes have killed more than 900 in Syria

Nearly all of those killed were militants, the group says

52 civilians are among dead

The U.S. and its allies began airstrikes two months ago

In the two months since the United States and coalition allies first launched airstrikes against ISIS targets inside of Syria, the missions have killed more than 900 people, nearly all militants, a monitoring group said Saturday.

But 52 civilians, including eight children and five women, are among those who have been killed in the coalition airstrikes inside Syria, the Syrian Observatory for Human Rights said.

The London-based organization is aligned with the Syrian opposition.

The United States had mostly stayed out of the Syria's civil war, which has been ongoing since March 2011, but as the battlefield fractured with the entry of jihadists like ISIS, the calculus changed.

Of the 910 deaths the observatory has linked to the airstrikes, some 785 were ISIS fighters. That number is likely even higher because of incidents in which the group had difficulty documenting.

Seventy-two of those killed belonged to the al Qaeda affiliate al-Nusra Front, the observatory said, and one was a militant from the Islamic Battalions.

More than 191,000 Syrians have been killed in the civil war, as of August, according to the United Nations.