Hundreds of prisoners have taken over the main jail in the Central African Republic capital of Bangui.
Security forces and international peacekeepers quickly surrounded Ngaragba prison, after which the United Nations mission in the country said the prisoners cannot escape.
There may still be more than 700 prisoners inside the detention center, which was built to accommodate only 300 prisoners.
Map of Central African Republic
The prison has seen breakouts in the past year, and the U.N. has been warning in recent weeks that conditions inside the jail might lead to further trouble.
On Monday, that trouble erupted.
The prisoners, some with weapons, took over the jail, exchanged gunfire with security forces outside the facility, and demanded talks with the head of the C.A.R. prosecution service.
Issue behind rioting
One of the policemen standing guard outside the jail told VOA, on condition of anonymity, what he thought had sparked the protest.
The policeman said one of the prisoners had died of tuberculosis so the prisoners have, as he puts it, gone on strike. They are demanding their rights, he said, as some of them have been held there for 10 months without trial.
The policeman also said some prisoners had been firing at peacekeepers and throwing grenades, and one Burundian peacekeeper had been wounded.
As of midday Wednesday the situation was calm, but the standoff continued.
Police Lieutenant Leo Franck Gnapie is with the U.N. mission in the C.A.R.
Gnapie said the prisoners aren't under control, as they are in the prison courtyard. But he insisted the prisoners are not outside and cannot get out because the jail has been sealed off.
Gnapie confirmed there have been casualties.
He said 13 people have been wounded and evacuated from the area, but most do not have gunshot wounds, as they were injured during rioting in the jail.
The incident is another sign of the chaos in the C.A.R., 20 months after Seleka rebels ousted the president. A transitional government has been unable to restore order or stop rampant violence and lawlessness around the country.
Recently, the U.N. told VOA there used to be 60 prisons in the C.A.R., but many were damaged or destroyed by rebels over the past two years and now only four of them are operational.
Ngaragba prison was the biggest of those four and for the time being it, too, is out of service.