Prison staff on alert for reprisals in wake of Woolwich murder One prison source said: "It is telling everyone to be alert following the events of last Wednesday and Sunday. It asks people to review their policies and risk assessments and to be aware of any staff who are ex-servicemen. Counter-terrorism officers have been called in to investigate the incident at Full Sutton, Yorkshire, suggesting it is being treated as an ideologically motivated attack. A male officer was allegedly grabbed by three Muslim prisoners near the kitchens on Sunday afternoon and held hostage for four hours. He suffered broken cheekbone and several wounds to his face and neck during the incident. A female officer also received cuts to her arm as she tried to help her colleague. The incident ended after specially trained officers entered the prison and released the man. A source said it was suggested the attack following anger after the imam request two days earlier. They also said staff raised concerns about rising tensions in the prison over the weekend. Officers from the North East Counter Terrorism Unit (CTU) are now interviewing the prisoners involved, two of who are aged 25 and one is 26. At least one is understood to have converted to Islam while behind bars and none of the men are serving sentences for terrorism related offences. Steve Gillan, general secretary of the Prison Officers Association (POA), said: "The POA are aware of the attack on two prison officers at HMP Full Sutton. Until the full facts of the incident are known, we do not wish to speculate or indeed compromise an ongoing police investigation. We can confirm that officers sustained injuries and, had it not been for the professionalism of prison officers dealing with this violent incident, the outcome could have been worse. Michael Spurr, chief executive of the National Offender Management Service, said: "This was a serious incident and my first thought is with the officer who was taken hostage - we will do all we can to help him recover from this experience. I want to commend all staff involved for their great courage and professionalism. The attack came amid increasing tensions in the wake of the Woolwich murder. Fierce protests from differing factions on the streets of London, attacks on mosques and vandalism against war memorials have all been triggered by the horrifying incident.