BEIRUT (REUTERS) - Islamic State in Iraq and Syria (ISIS) militants have kidnapped scores of workers in an area north-east of Damascus after launching an attack on government forces there this week, Syrian state television and a monitoring group said on Thursday.

State TV quoted the industry ministry as saying 300 workers and contractors of Al Badia Cement were taken from near the town of Dumeir and that the company had lost all contact with them.

The British-based Syrian Observatory for Human Rights later gave a figure of around 170 workers who had been abducted from the cement factory and taken to undisclosed areas controlled by the militants in the Damascus suburbs.

The monitor, which tracks violence across the country, said 140 workers at the plant had fled before the militants arrived.

Fierce fighting broke out around Dumeir and the nearby military airport, 50km north-east of the capital, late on Tuesday night after ISIS militants launched attacks on government areas northeast of the capital.

Opposition sources in the rural eastern suburbs of Damascus said militants in Dumeir fired at civilians protesting against their presence in the town and at the abductions.

The town was mostly already in the hands of squabbling rebel groups including groups that are affiliated to Islamic State.

Hundreds of families had fled since the militant assault, the sources said.

The attacks on Tuesday and Wednesday included detonation of bomb-laden cars around the Dumeir military airport and an assault on the nearby Tishrin power station.

Syrian and allied forces backed by Russian air strikes this week forced Islamic State militants out of al-Qaryatain, which lies between Damascus and the ancient city of Palmyra, itself recaptured by the government last week.