At least one Daesh terror group car bomb killed dozens of people at a refugee gathering on the east side of the Euphrates River in Syria on Saturday, the British-based Syrian Observatory for Human Rights said.

It said the blast also caused many injuries and took place in Deir el-Zour, between the Conoco and Jafra energy fields, an area controlled by the U.S.-backed, PKK's Syrian offshoot People's Protection Units (YPG)-dominated Syrian Democratic Forces (SDF).

Observatory head Rami Abdel Rahman said he could not immediately give a specific toll of how many people were killed and wounded in the attack.

Abdel Rahman said the victims had fled battlegrounds in Deir el-Zour province.