NICOSIA: At least 25 inmates were shot dead by Syrian security forces during a riot by political detainees at a prison in mountains outside Damascus on Saturday, a human rights group said.

“Islamist prisoners started a riot inside the prison this morning,” the Syrian Observatory for Human Rights said in a statement received in Nicosia, quoting a political prisoner in the Saydnaya jail contacted by mobile phone. “Shooting is continuing against the prisoners,” the London-based group said, adding that a number of inmates had climbed the roof of the military prison north of Damascus to escape the violence.

Helicopters were buzzing the facility near the hilltop village of Saydnaya, about 30-km from the capital. The Observatory, which is close to the opposition, said initially that the number of dead was 10 but a spokesman later telephoned AFP to say that the toll had risen to 25. The Observatory said about 400 detained soldiers were being held hostage in the prison as bargaining chips to apply pressure on Syrian authorities.

The group said it was also receiving phone calls from relatives of prisoners asking Syrian President Bashar al-Assad to intervene to stop the clashes in Saydnaya, an ancient town with biblical connections. There was no immediate comment from the Syrian authorities.