Riot police members keep guard over Abogado Antonio Jacinto Filho high security Penitentiary Complex, in the city of Aracaju, regional capital of Sergipe northwest state, Brazil, on April 16, 2012. Over 450 prisoners rioted inside the penitentiary complex as a protest over aggressions inflicted by prison security guards. Protesters took three security guards as hostages, reported local media. [Xinhua]