The self-styled Islamic State militant group has released 270 of more than 400 civilians it had abducted during its assault on the eastern Syrian city of Deir Ezzor, according to a monitoring group.
Those released included women, children under 14, and the elderly, Rami Abdel Rahman, head of the British-based Syrian Observatory for Human Rights, said.
He said they had been freed after undergoing questioning by IS jihadists to determine whether they had ties to Syria's regime.
"They will not go back into Deir Ezzor city, but will be spread out among local tribes in the province," Mr Abdel Rahman said.
IS is still holding 130 civilians, mostly teenage and adult men.
Mr Abdel Rahman said: "If IS sees that they have no ties to the Syrian government, they will take a religious course and will be released."
IS launched a multi-pronged assault on Deir Ezzor city on Saturday with dozens of its fighters carrying out suicide bomb attacks as they stormed government positions.
The group is now in control of 60% of the city and has tightened its siege around it by capturing surrounding towns.
As IS overran Al-Baghaliyeh, an agricultural area northwest of the city, it abducted another 50 people, mostly men, Mr Abdel Rahman said, but it was not immediately clear whether they were civilians or pro-regime fighters.
