A medical source in the Kurdish Red Crescent said ISIS suicide bombers killed at least 50 people in a triple car bomb attack Thursday in northeastern Syria.

The source added that a large number of people were also injured in the attack.

The car bombing targeting displaced Syrians in the province of Hasakeh was reported to have killed at least 18 people earlier, including Kurdish security forces, according to the  Syrian Observatory for Human Rights.

The Britain-based monitor said the attack was carried out by ISIS and took place in an area where Syrians displaced from Deir Ezzor province usually gather.

“At least 18 people, including displaced persons and members of the Asayesh Kurdish security forces, were killed,” Observatory head Rami Abdel Rahman said.

Two separate offensives targeting ISIS are underway in the eastern oil-rich province of Deir Ezzor, one by Russia-backed government forces and the other by US-backed Kurdish-Arab fighters known as the Syrian Democratic Forces (SDF).

SDF spokesman Talal Sello confirmed a car bombing targeting people displaced from Deir Ezzor, saying it took place in the Hasakeh’s southern area of Abu Fass.

“Dozens of people were killed and wounded,” Sello told AFP.

After the blast, “the civilians escaped towards desert areas where mines exploded and the toll rose”, he added, without providing further details.

Much of Hasakeh province and Hasakeh city are under the control of a Kurdish “autonomous administration” with smaller parts of both controlled by the central government.

Abu Fass is where Kurdish authorities gather people displaced by conflict before allowing them to enter camps where they can shelter, the Observatory said.

Earlier Thursday, the monitoring group, which relies on a network of sources inside war-torn Syria, said regime forces had retaken four neighborhoods in the town of Mayadeen in Deir Ezzor province.

The state news agency SANA confirmed that regime forces had re-entered Mayadeen.

Last week, ISIS succeeded in expelling Syrian forces from Mayadeen two days after they entered the town.

A Syrian army source had recently described Mayadeen as the “military capital” of ISIS in Deir Ezzor

source: Alarabiya