Officials called in counter terrorism police to Whitemoor today following an assault on a prison officer by two inmates.
Five members of staff who went to the rescue of the officer were later taken to hospital.
A prison service spokesman said: "The incident was quickly resolved by our brave staff and our thoughts are with the injured officers at this time."
The Met Police told the BBC its counter terrorism command unit had been sent to Whitemoor "due to certain circumstances relating to this incident".
A Met Police spokesman said it was "deemed appropriate" to call in counter terrorism officers to investigate.
He told the BBC: "However, we must stress that at this early stage of the investigation we are keeping an open mind with regards to any motives and enquiries to establish the full circumstances of the incident are ongoing."
The prison service spokesman added: "We do not tolerate assaults on our hardworking officers and will push for the strongest possible punishment."
Violence at the prison nearly a year ago resulted in some staff receiving medical treatment.
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