Inmates at a prison in southern Brazil on Monday took seven prison staff hostage during the latest in a series of mutinies at penitentiaries in recent months, Brazilian media reported.
Officials, quoting state justice officials, said one of those detained was released Monday evening with minor injuries after the seven were taken hostage during disturbances which began mid-afternoon at Maringa prison in the southern state of Parana, some 600 kilometers (370 miles) west of Sao Paulo.
Contacted by AFP, prison staff could not confirm if any further hostages had been released in the second mutiny by inmates of the facility, built in 1996 and which holds 650 prisoners, in just over two months. A spokeswoman said police were at the scene.
Web news portal G1 indicated military police were negotiating with the mutineers in a wing of the jail holding 120 prisoners.
According to the state justice ministry, the jail is not quite full to capacity in currently holding 636 detainees.
Monday`s unrest was only the latest in a series of prison mutinies across Brazil in recent months.
As well as disturbances in Maringa itself in late October, the same month saw two days of unrest at Guarapava, also in Parana state, which ended with the release of guards and inmates whom other prisoners had taken hostage.
Quoting the state justice secretary and regional prison officers` union, Sindarspen, broadcaster Globo reported that the past five months have seen 23 prison mutinies in Parana state alone.
At Cascavel jail, also in Parana, five prisoners were killed -- two of them beheaded -- in two days of rioting in August, with material damage on such a scale that hundreds of inmates had to transferred.
In the northern city of Sao Luis de Maranhao, the infamous penitentiary of Pedrinhas has been the frequent scene of prison violence and escape attempts while further unrest saw two prisoners slain at a jail in the northern region of Amazonia.
With more than 560,000 prisoners nationwide, Brazil`s jails are bursting at the seams with 274 people in prison per 100,000 residents, according to the International Centre of Penitentiary Studies.
The NGO Conectas said earlier this year the country needs to boost capacity by 207,000 to overcome severe overcrowding.
According to Amnesty International, Brazil has the fourth largest prison population in the world, after the United States, China and Russia.