An inmate has been injured during a disturbance at a jail that led to riot officers being called in.
Specialist "Tornado" squad officers were brought in at HMP Swaleside, on the Isle of Sheppey, Kent, on Sunday.
A small number of inmates on one wing were involved in the violence, which has since been "successfully resolved", the Prison Service (PS) said.
Almost a year ago, up to 60 inmates took over part of the prison for 12 hours.
On the latest incident, the PS said: "We do not tolerate violence in our prisons and are clear that those responsible will be referred to police and could spend longer behind bars."
In September, a report revealed there had been an "unacceptable escalation of instability" at the jail.
The HM Inspectorate of Prisons said there had been too many assaults on both staff and prisoners and the smuggling of weapons was an issue.