Two prisoners have been shot dead during an attempted jail break in the northern Nigerian city of Kaduna, officials say. The BBC's Nurah Mohammed in Kaduna said he saw one wounded prison guard being taken to a nearby infirmary, along with several wounded prisoners. Our correspondent said prisoners started a fire, which burnt down some offices and a workshop in the prison. This is the second attempted jail break in Kaduna in the past few months. There were reports of shooting and a loud explosion, and security forces surrounded the jail in an attempt to restore control. The controller of Nigeria's prisons has arrived on the scene and confirmed earlier reports of the two deaths and said 39 had been wounded. However, our correspondent says people working inside the prison told him there were more than 50 injured, some quite seriously. The police commissioner has blamed the attempted jail-break on a prisoner who was transferred recently to Kaduna from Lagos, our correspondent reports. The prisoner is awaiting a death sentence and has a history of stirring up unrest among his fellow inmates, the police commissioner said. Officials have confirmed the prisoner is safe and has been transferred to another jail in Kaduna. Prisoners in Kaduna have complained about overcrowding and poor treatment. Source: BBC