Airstrikes by U.S.-led forces in Syria have killed 910, including 52 civilians, since they launched their offensive Sept. 23, the Syrian Observatory for Human Rights reported Saturday. The U.K.-based group monitoring casualties in the country said the 52 civilians included eight children and five women. The organization condemned the civilian deaths that resulted from the coalition airstrikes.

The observatory, collecting its information from contacts on the ground in Syria, reported the U.S.-led air campaign killed 785 Islamic State fighters, most of whom were not Syrian. It also said 72 Jabhat al-Nusra militants had been killed as a result of the airstrikes. The Nusra Front is a group aligned with al Qaeda and operating in Syria and Lebanon.

Additionally, the observatory reported “the coalition airstrikes targeted oil refineries and oil fields in Der-Ezzor, al-Hasakah and al-Raqqa, [which] led to material damages in these refineries and oil fields.”

American officials have said they have targeted the so-called Khorasan Group in Syria. It has been described as a collective of al Qaeda leaders operating under the protection of the Nusra Front, Reuters reported. Officials have said the group includes al Qaeda operatives originally from Afghanistan and Pakistan who have entered Syria. Khorasan is a historical term for an area including parts of Afghanistan and Pakistan.

U.S. officials have said Washington takes reports of civilian casualties seriously and that it has a process to investigate reports of any such deaths, Reuters reported.