Rio de Janeiro, Aug 25 (IANS/EFE): Four prisoners were killed, two of them decapitated, and an undetermined number injured in a prison rebellion in Parana state in southern Brazil. Authorities are also negotiating the release of two hostages, official sources reported.

Some 800 of the prison's 1,400 inmates are taking part in the uprising at the state penitentiary of Cascavel city to demand better infrastructure, food and hygiene as well as an end to alleged abuses by prison guards.

The rebels decapitated two of the prisoners, including a former policeman, and threw three people from a roof, two of whom died in hospital, the Parana Penitentiary Department (Depen) said.

The riot began early Sunday when one of the prison guards was taken hostage as he was about to serve breakfast.

Although the prisoners had threatened to stage a protest, only 10 guards were in charge of the jail at the time of the incident.

The prisoners occupied the building's roof, where they took the hostages and set fire to several mattresses.

The military police in Parana has surrounded the penitentiary, pending negotiations conducted by Depen officials.

The rioters put the initials PCC on the roof, alluding to the First Command of the Capital, the largest criminal organisation in Sao Paulo, that is ruled from prisons.