At least 75 civilians were killed in an Islamic State group car bombing that struck a gathering of people displaced by fighting in eastern Syria, a monitor said on Sunday.
Saturday's attack in the eastern province of Deir Ezzor killed "at least 75 displaced civilians including children" and wounded 140, said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights.
Abdel Rahman said the victims had fled battles in the province, where Syrian regime forces and a US-backed Kurdish-Arab alliance, the Syrian Democratic Forces, are fighting the extremist group in separate offensives.
The Britain-based war monitor, which relies on a network of sources on the ground inside Syria for its information, reported on Saturday that dozens had died in the blast.
Fighting across Deir Ezzor province has sent thousands of civilians fleeing for their lives, some straight into the desert.
Some had sought refuge in a desert area controlled by the SDF on the eastern bank of the Euphrates River where the Saturday bombing struck.
It was not the first attack attributed to IS against civilians fleeing Deir Ezzor.
On October 12, a car bombing in the northeastern province of Hasakeh killed at least 18 people, including displaced people and Kurdish security forces, the Observatory said.
Sonia Khush, Syria director at the Save the Children charity, said on Saturday an estimated 350,000 people have fled the recent fighting in Deir Ezzor province, half of them children.
"The situation in the city, and surrounding countryside, has been especially bleak with civilians trapped between the fighting and all too often caught in the crossfire," she said.