One prisoner was killed as inmates staged a protest demonstration in Afghanistan's southern Helmand province on Tuesday, provincial police Chief General Nabi Jan Mullahkhil said.
Inmates say that police firing left one prisoner dead in Helmand's central jail in the provincial capital Lashkargah, Mullahkhil told Xinhua.
However, he added that investigation is underway to find the fact.
Accusing the jail officials of highhandedness and applying maltreatment, the inmates said that warders and jail officials treat them inhumanly.
Around 300 peoples including criminals and Taliban-linked militants were held in Helmand's central jail.
"We are trying to find a peaceful solution to the problem through negotiation with the inmates," Mullahkhil added.
Similar riot in Kabul central Pul-e-Charkhi prison left four persons dead and injured 17 others early this year.