Syrian dissident writer and journalist Akram Bunni has been arrested by the security forces, his brother, a prominent rights lawyer, told AFP Sunday. The 58-year-old Christian former political prisoner who had been forbidden from leaving the country, "was arrested at noon Saturday in the heart of Damascus by the state security services," Anwar Bunni said. He said he did not know why his brother was arrested. On his Facebook page, Anwar Bunni demanded his release: "Freedom for Akram al-Bunni. Freedom for all detainees. Freedom for Syria," he wrote Rights groups say tens of thousands of people are being arbitrarily held in Syria's jails, including many rights defenders and peaceful activists. Akram Bunni has been imprisoned several times. He was jailed from 2007 to 2010, alongside 11 other dissidents, for signing the so-called Damascus Declaration demanding democratic radical change in Syria. A member of the banned Party for Communist Action, he was also jailed from 1978 to 1980, and again from 1987 to 2001, when Syria was ruled by former president Hafez al-Assad, President Bashar al-Assad's father. Syria's revolt began in March 2011 as a peaceful uprising demanding political change, but morphed into an insurgency after Assad's regime unleashed a brutal crackdown against dissent.