Around 250 Syrian civilians are feared kidnapped after an attack by the "Islamic State" (ISIS) terrorist group on a cement factory east of Damascus, residents told AFP on Thursday.

"We haven't been able to reach our family members since noon on Monday after an attack by Daesh on the factory," said a resident of the town of Dmeir, 50 kilometers east of Damascus, using the Arabic acronym for ISIS.

An administrator at the plant said 250 employees had been unreachable since Monday.