IS releases 270 kidnapped civilians in Deir Ezzor

The Islamic State militant group has released more than half of the people it kidnapped over the weekend in Syria, freeing 270 of the 400 people taken in the city of Deir Ezzor, a Syrian rights group said.

Among the released were women, children under the age of 14 and men over the age of 55, said Rami Abdurrahman, director for the Syrian Observatory for Human Rights. CNN cannot independently confirm the rights group's reports.

Fighting in Deir Ezzor intensified recently, including suicide bombings, mass abductions and arbitrary killings, rights activists have said. They had initially feared that all 400 of the civilians reported kidnapped had been killed.

Most of the city has been controlled by IS for well over a year, but some neighborhoods and the military airport to the south have remained in the hands of the regime.

Inside the city, IS has been chipping away at the Syrian regime's remaining positions, tunneling under them and attacking checkpoints with suicide bombs.

Deir Ezzor is a critical junction for the group, with roads east and south toward Iraq and west to areas it controls in Homs province, including Palmyra. It is also surrounded by some of IS' most valuable oil fields, which have been intensively targeted by both U.S. and Russian air power in recent months.