Russian authorities say they have quashed a riot at a pretrial detention center in the Ural mountains city of Chelyabinsk.
Officials at the facility said on December 9 that around 100 prisoners had maimed themselves or set their mattresses on fire in protest after an inmate was placed in solitary confinement for refusing to obey guards.
The officials denied relatives' claims that guards had severely beaten inmates at the facility.
The Russian prosecutor-general's office said that senior regional and city proscecutors were investigating the incident.
Unrest is common at Russia's overcrowded prisons and pretrial detention facilities.