Around 300 Syrian civilians are feared kidnapped after an attack by the Daesh terrorist group on a cement factory east of Damascus, residents on Thursday said.

"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 (30 miles) east of Damascus.

"We have no information about where they are," the resident added.

An administrator at the plant said 300 employees had been unreachable since Monday.

The Syrian Observatory for Human Rights said "dozens" of staff were believed to have been seized by Daesh from the cement factory and taken to an unknown location.

The Badiyah cement factory lies outside Dmeir, which has seen fierce fighting in recent days as government forces have shelled Daesh positions inside the town.

The Observatory said 18 civilians were killed in government shelling of the town.

A Syrian security source said that Daesh fighters had also tried to seize the nearby Dmeir airbase and power plant from the government but had failed.