Riot squad called to prison in Birmingham, England

Security staff carry equipment into HMP Birmingham, in Birmingham, England, Friday, Dec. 16, 2016. Security firm G4S, which runs HMP Birmingham, has deployed a specialist riot squad to a prison the English city of Birmingham after disturbances by inmates spread to four wings of the facility. The disturbance began at about 9 a.m. GMT (0400 a.m. EST) Friday. The unrest comes at a time that Britain's prisons are under intense pressure. Members of the Prison Officers Association say violence and inmate suicides are rising. (Joe Giddens/PA via AP) (The Associated Press)

A broken window is seen at HMP Birmingham, in Birmingham, England, Friday, Dec. 16, 2016. Security firm G4S, which runs HMP Birmingham, has deployed a specialist riot squad to a prison the English city of Birmingham after disturbances by inmates spread to four wings of the facility. The disturbance began at about 9 a.m. GMT (0400 a.m. EST) Friday. The unrest comes at a time that Britain's prisons are under intense pressure. Members of the Prison Officers Association say violence and inmate suicides are rising. (Joe Giddens/PA via AP) (The Associated Press)

Smoke rises above HMP Birmingham, in Birmingham, England, Friday, Dec. 16, 2016. Security firm G4S, which runs HMP Birmingham, has deployed a specialist riot squad to a prison the English city of Birmingham after disturbances by inmates spread to four wings of the facility. The disturbance began at about 9 a.m. GMT (0400 a.m. EST) Friday. The unrest comes at a time that Britain's prisons are under intense pressure. Members of the Prison Officers Association say violence and inmate suicides are rising. (Joe Giddens/PA via AP) (The Associated Press)

Security firm G4S has deployed a specialist riot squad to a prison the English city of Birmingham after disturbances by inmates spread to four wings of the facility.

G4S is a private company which runs the prison.

The disturbance began at about 9 a.m. GMT (0400 a.m. EST) Friday.

The unrest comes at a time that Britain's prisons are under intense pressure. Members of the Prison Officers Association say violence and inmate suicides are rising.

Some 200 prisoners rioted last month at Bedford Prison in southern England and guards also staged a walkout before courts ordered them to return to work. The prison officers union says "the service is in meltdown," with poor morale making it hard to retain staff.