Prison staff are involved in a stand-off with inmates following a disturbance at a jail.
An unknown number of prisoners refused to return to their cells at the end of the evening at HMP Birmingham, a category B and C jail.
A spokesman for G4S, which runs the jail, said: "Our teams are responding to an incident on one wing at HM Prison Birmingham.
"We are working with colleagues from Her Majesty's Prison and Probation Service to bring the incident to a safe conclusion."
No staff are believed to be hurt.
It came after some 240 prisoners were moved out of HMP Birmingham, one of the country's biggest jails, on Friday.
Hundreds of inmates were caught up in the disorder and four wings at the privately-run jail were damaged during the disturbances, which lasted for more than 12 hours.
Riot squads were deployed to the prison after reports of prisoners setting fire to stairwells and destroying paper records.
The city centre jail, formerly known as Winson Green, can hold up to 1,450 inmates.
One man, believed to be in his 20s, was taken to hospital with a facial injury as well as cuts, bruises and a reduced consciousness, West Midlands Ambulance Service said. No prison staff were injured.
G4S has run the prison since 2011 when it became the first public-sector jail to be privatised.
A Prison Service spokesman said the incident involved "a small number of prisoners".
He added: "Prison staff are working to resolve it quickly and safely. There is no risk to the public."