Brasília (AFP) - Inmates at a Brazilian prison took 12 guards and several fellow inmates hostage in the latest of a series of uprisings.

Police and a judge negotiated with the inmates Monday evening at the prison in southern Parana state, and later suspended the talks until Tuesday morning, said the regional secretary of state for justice Elson Faxina.

He said the reasons for the riot were not immediately known.

But press reports said the inmates at the Guarapuava prison want better living conditions, and the transfer of prisoners doing time for sexual offenses to other jails.

Globo News TV footage showed three people, apparently guards, semi-naked and seated on top of a prison building. They were tied up, and watched over by inmates who covered their faces with T-shirts.

The riot is the fifth in jails in Parana in barely a month and the 21st this year, according to the regional prison officer's union, Sindarspen.

In this uprising, one guard was hurt and sent to a hospital when prisoners hurled hot glue at him, the union said.

In August, a two-day riot by inmates in the town of Cascavel saw five prisoners killed -- two of them beheaded.

In the northern city of Sao Luis de Maranhao, the infamous penitentiary of Pedrinhas has seen violence and many attempts to escape brutal conditions, while last month saw two prisoners slain at a jail in the northern region of Amazonia.

With 548,000 prisoners nationwide, Brazil's jails are bursting at the seams.

There are 274 people in prison per 100,000 residents, according to the International Centre of Penitentiary Studies and NGO Conectas says the country needs to boost capacity by 207,000 to deal with severe overcrowding.

"The Parana prison system is in major crisis," Sindarspen said in a statement.

The union added that prison officers fear for their personal safety "and we don't know if we'll make it home after our shifts."