U.S. strikes pro-Assad forces in Syria after SDF is attacked

American aircraft carried out retaliatory strikes in Syria against forces loyal to President Bashar al-Assad on Wednesday, U.S. officials said.

Syria's state-run SANA news agency reported that the bombing left dozens of people dead and wounded. NBC News could not immediately confirm that account.

US launches airstrikes in Syria 0:20

No embedded U.S. troops were believed to have been wounded or killed in an earlier attack targeting a headquarters of the American-backed and Kurdish-led Syrian Democratic Forces, U.S. officials told Reuters on condition of anonymity.

The SDF is an alliance of militias in northern and eastern Syria.

The U.S.-led coalition fighting Islamic State militants did not say whether any pro-Syrian fighters were killed in the retaliatory strike.

The coalition described the attack on the SDF headquarters as "unprovoked," but offered little other information in a terse statement confirming the incident.

SANA reported that the overnight strikes hit tribal fighters who back Assad in Khusham, a town in oil-rich Deir el-Zour. SANA said the local fighters were battling Islamic State militants and the SDF.

The Syrian army is backed by Iranian-backed militias and Russian forces.

Image: Map shows location of Deir el-Zour
A map showing the location of Deir el-Zour in eastern Syria. Google Maps