Specialist officers sent to Hertfordshire prison riot
Tornado Teams are understood to be dealing with the incident at HMP The Mount.
Specialist officers are dealing with a disturbance that has broken out among inmates at a Hertfordshire prison.
The Ministry of Justice (MoJ) said staff were working to resolve the incident at HMP The Mount.
Tornado Teams - elite officers trained to bring riots under control - are understood to have been sent in to deal with the incident.
The MoJ said the prison remained "completely secure".
A prison service spokesperson said: "Specially trained staff are working to resolve an incident involving a number of prisoners at HMP The Mount.
"The prison is completely secure and there is no risk to the public."
The Mount is a Category C prison in Bovingdon which holds more than 1,000 inmates.
It is described as "a hybrid training and resettlement prison, catering for a number of prisoners in the last six months of their sentence who are residents of Hertfordshire and surrounding areas".