Reports that Islamic State militants have massacred 175 captured workers from a cement plant near Damascus have been withdrawn.

The news agency, Reuters, this morning quoted the Syrian military as suggesting the plant workers had been killed by the militants

But minutes later the agency withdrew the report.

The workers were captured at the Al Badia Cement company, near the town of Dumeir, 30 miles northeast of the capital Damascus.

Contact has been lost with the employees, and it is not known what has happened to them.

Their capture took place in the same area where IS militants launched an assault on Syrian President Bashar al Assad's forces on Tuesday night.

They reportedly captured much of Dumeir, including its military airport and power station.

Hundreds of families have fled the area, according to opposition sources.

Sky's Foreign Affairs Editor Sam Kiley said the capture of the power plant workers was unusual and was probably in response to President Assad's advances in the ancient city of Palmyra.

"This is interesting because actually Islamic State have worked hand in glove in the past with the government, particularly in power stations," he said.

(Sky News)