Thirteen inmates were hurt in mass disturbances at a penitentiary in Russia's Samara region, spokesman for the regional Penitentiary Service department Artur Malivanchuk told Itar-Tass on Wednesday. At 19:30, on Tuesday, a number of inmates at maximum regime penitentiary # 6 at Upravlenchesky village, Krasnoglinsky district, torched several wooden watch towers and the former headquarters, used for hobby group classes and as a storage facility. Prison personnel provided medical assistance to the injured. Four inmates who suffered wounds were hospitalized, and another two were treated for minor burns. The prison staffs were not harmed. At present, the penitentiary is under complete control, Malivanchuk said noting that one-third of the inmates were serving 15-year or longer sentences. Irina Doroshenko, senior aide to the director of the regional department of the Investigations Committee, said a criminal case had been opened under two articles: "disruption of operation of penitentiary," and "mass rioting." A probe is underway.