Syrian government troops have stormed a prison in the central city of Hama to try to put down a mutiny among some 800 inmates, the BBC quoted monitoring groups as saying on Friday.
The mutiny began on Monday when inmates took some guards hostage.
Troops surrounded the facility after the guards were taken on Monday, the Observatory said.
It said prisoners were also angry at delays to trials.
Some 46 prisoners had been released since the protest began, it said.
More than 270,000 people have died in five years of conflict in Syria.
A nationwide, and very shaky, partial truce agreement between government forces and non-jihadist rebel groups has been in place since February.
Source : MENA