Bosses at security firm G4S, which runs HMP Oakwood in South Staffordshire, have put contingency plans in force as a rooftop protest continues at the prison.
A spokesman confirmed six prisoners were involved in the incident.
We can confirm that an incident involving six prisoners is taking place at HMP Oakwood.
The Ministry of Justice has been alerted and our normal contingency plans have been enacted.
More top news
Five NHS trusts in the Midlands have come under fire after it emerged bosses were sitting on more than £134 million of spare cash.
Cold with wintry showers mainly affecting Lincolnshire. Elsewhere, mainly dry but frosty.
There may be some sleet or snow tonight, but generally dry with clear spells.