The self-styled Islamic State group abducted at least 400 civilians when they attacked government-held areas in the Syrian city of Deir al-Zor yesterday, according to a monitoring group.
The Syrian Observatory for Human Rights said: "After their attack on Deir Ezzor, IS abducted at least 400 civilians from the residents of the Al-Baghaliyeh neighbourhood it captured and adjacent areas in the northwest of the city.
"Those abducted, all of whom are Sunnis, include women, children and family members of pro-regime fighters," the observatory chief said, adding they were transported to other areas under IS control.
Earlier, Syria's state news agency SANA said that at least 300 people had been killed in the attacks in Deir al-Zor.
Meanwhile, there has been an outpouring of support on social media for an elderly Australian couple abducted by suspected Islamists in Burkina Faso.
Dr Ken Elliot and his wife Jocelyn, who are in their 80s, were kidnapped on Friday in northern Burkina Faso near the border with Mali.
It is not yet clear if their kidnapping is linked to an attack on a hotel in the country's capital on the same day which left 29 people dead.
Six Canadians, two French citizens, two Swiss nationals and one American were among those killed.