Full Sutton Prison Guard 'Kidnapped And Beaten' Police are investigating after prisoners at a maximum security jail kidnapped a guard for four hours and gave him a severe beating. Three Muslim prisoners, two aged 25 and one aged 26, were believed to have been involved in the attack, which is being investigated by counter-terrorism officers. The National Offender Management Service said none of the inmates is serving a sentence for terror-related offences. The guard suffered a broken cheek bone and wounds to his face and neck and was reportedly only freed after prison officers in riot gear stormed a cleaning room where he was being held. A prison service spokesman said: "An incident involving three prisoners took place at HMP Full Sutton on May 26 from 4.25pm and was successfully resolved at 8.40pm after staff intervened. A police investigation is ongoing. A female guard was also injured as she tried to stop the inmates from dragging away her male colleague, who is in his 30s. A watchtower at the maximum security jail near York Both prison officers were treated for their injuries and have since been discharged from hospital. The Ministry of Justice confirmed that Parviz Khan - linked to the attack by two national newspapers - is not a prisoner at the jail and was not involved in the incident. Khan is currently serving life for plotting to kidnap and behead a Muslim member of the Army - a plan which is thought to have inspired the murder of Drummer Lee Rigby in London last week. Full Sutton governor Paul Foweather was kept informed as officers locked around 600 inmates in their cells and tried to calm the situation. The North East Counter Terrorism Unit confirmed it was taking the lead role in investigating the attack. The attack is not thought to be directly connected to the killing of Drummer Rigby in Woolwich. Police said in a statement: "Given the potential nature of the incident and the range of skills and expertise within the North East CTU, the unit is leading the investigation at this time." Full Sutton is a maximum security prison holding some of the most dangerous category A and B inmates in the country - including dozens of terrorists. It has an operational capacity of 608 and does not normally accept prisoners sentenced to less than four years. Prison inspectors have criticised the staff/prisoner relationship and were concerned about some of the practices in the segregation unit. After the last inspection in 2011, inspectors said: "Relationships between staff and most prisoners had improved, supported by a good personal officer scheme, regular consultation and an impressive mediation initiative. However, despite satisfactory diversity structures, Muslim and black and minority ethnic prisoners reported much more negatively than their non-Muslim and white counterparts on a range of issues. The chaplaincy continued to provide a valued service, including working sensitively and effectively to support Muslim prisoners while challenging attempts at radicalisation.