At least 175 of the 300 workers kidnapped by the Islamic State are believed to have been killed in a town northeast of the capital Damascus, the media reported on Friday.
The 175 victims were among workers the IS had taken hostage in a sprawling cement factory in the town of Dumair, northeast of Damascus, Xinhua reported.
A day earlier, a total of 140 workers fled the IS captivity in the cement factory, spelling no further details about their whereabouts.
Earlier reports said a group of rebels, who pledged alliance to the IS, were behind the attack on the factory and a nearby airbase in Dumair.
The Syrian army has repelled the attack on the airbase, but the IS still controls the factory. Dumair is divided between Islamist groups and the Syrian army.
State news agency SANA also earlier reported the abduction incident, saying the Syrian authority was working on their release.
Still, the circumstances of the abduction and the fate of the workers are still murky, with no clear response from the government about the incident.