Beirut: President Bashar Al Assad’s key military unit in charge of protecting Damascus is running secret prisons holding hundreds of suspected regime opponents, a Syria-based human rights group said in a report on Monday.

The Violations Documentation Centre said the regime’s 4th Division runs detention centres in its bases in and around Damascus. The division is commanded by Maher Al Assad, the president’s younger brother. It is considered a pillar of loyalist forces and is charged with defending the capital, the seat of Al Assad’s power.

The Centre, which has tracked the dead, wounded and missing since the start of the uprising in March 2011, said it interviewed “several” former detainees, who had been held in small crowded cells and beaten by guards.

Bashar Al Ahmad, a 31-year-old schoolteacher, said he was taken blindfolded to the detention centre and realized after he was arrived that he was underground. He said guards started beating him with batons, electric prods and cables “the moment we arrived.” The report said Al Ahmad was accused of human right activism.

The Centre’s claims could not be independently verified, but other rights groups including the US-based Human Rights Watch have said thousands of opposition members, protesters and their families have been detained since the revolt against Assad’s rule started in March 2011.

Syria’s government rarely comments on claims by such groups.

None of the former detainees were able to give the exact location of the secret prison because they said they had been blindfolded during transfer there from an intelligence branch, the report said. They also said they had been held in small cells crammed with dozens of other prisoners.

The report did not say when the detentions occurred. Fighting has flared in recent weeks in the suburbs of Damascus as regime forces move against neighbourhoods used by rebel groups to threaten the capital, the seat of Al Assad’s power.

Syria’s two-year conflict that’s started as peaceful protests against Al Assad’s autocratic regime that turned into civil war in which more than 70,000 people have been killed, according to the United Nations.