Isis announces massacre of captives from Syrian cement factory after majority of 300 workers 'released'

The group's claim it had executed 24 Druze workers and 'regime supporters' could not be verified

The factory lies between regime, opposition and Isis territories (AP)

Isis claims to have massacred more than 20 people abducted from a cement factory in Syria after singling them out as non-Muslims and “regime supporters”.

There were fears that the so-called Islamic State may have murdered a far higher number of around 300 workers taken from the plant in eastern Qalamoun, outside Damascus.

Militants overran the area in an advance on Tuesday, when they failed to seize control of the nearby Dumeir air base and a power plant on the frontlines between regime and opposition territory.

Amaq Agency, which publishes Isis propaganda, released a statement saying at least 300 employees from the Al Badia Cement Company had been released but that more than 20 prisoners were killed.

A statement described fighters “interrogating” captives to identify alleged supporters of Bashar al-Assad and members of religious minorities.

“The fighters of the Islamic State transferred the workers to a safe place, where they received medical care and food, as well as being interrogated to identify the non-Muslims and to uncover the Syrian regime soldiers and supporters hiding in their midst,” it said.

“Islamic State fighters discovered twenty Popular Committee militiamen among them, as well as four Druze workers, who were then executed.”

The UK-based Syrian Observatory for Human Rights reported that all workers had been released apart from factory guards and gunmen who protected the area , who were held on charges of “dealing with regime forces” and would be punished.

The black symbols show the location of fighting at the factory, which lies on the frontline between Syrian government forces (red), rebels (green) and Isis (black) (Liveuamap)

Rami Abdul Rahman, the Observatory’s founder, told The Independent that Isis’ claims could not be confirmed and that the fate of around 30 workers from the plant was still unknown.

“More than 100 people escaped two days ago, then 170 people were released yesterday,” he added.

The latest group has reached safety in the city of Dumeir, which is beyond Isis territories, after mediation by local elders.

Conflicting reports on Friday claimed 175 workers had been massacred, with Russian state media quoting “sources on the ground” confirming the atrocity.

The number of those feared dead roughly matched the group who were still unaccounted for and have since been freed.

There has been no official statement from the Syrian regime, although state media reported that the workers had been taken to an “unidentified place” and that initial communication efforts by the Ministry of Industry had failed.

An Isis video claiming to have been taken inside the cement factory on Thursday showed diggers and lorries parked in a deserted depot, with Isis fighters milling around office buildings and the group's black flag fluttering at the entrance.

The body of a man dressed in military fatigues was shown lying on the ground.

According to Al Badia’s website, the plant started production in 2011 and employs 360 people.

Fierce clashes have erupted in the area in recent days between Isis, government forces and Syrian rebels.

Regime forces were in control of Dumeir air base on Saturday morning following an Isis suicide attack, while opposition rebels were battling to re-take territory recently gained by the so-called Islamic State.