At least six prisoners were killed and another six injured when Somali security forces beat back an uprising in Mogadishu's central prison on Monday, state radio reported.A senior police officer who did not wish to be named said that mutinous prisoners snatched guns from guards who were on duty on Monday evening, then killed three of them. The guards and other security forces regrouped and managed to kill the mutineers, the senior office said."The security forces shot dead six prisoners, injured six other prisoners and captured five others alive. They were all prisoners who fought in the cell," the state radio said on its website, quoting the security services.The operation to restore order in the prison complex had been completed, the radio reported.One inmate said he saw a soldier, who seemed to be wounded, lying prostrate on the grounds of the prison."I can hear the gunfire from inside the central cell block," Mohammed Nur, an inmate at the prison, told Reuters as he cowered in a separate room.Somalia has been trying to re-establish the rule of law in the past decade but still suffers from frequent attacks by al Shabaab militants. The group did not respond immediately to a request for comment by Reuters.