Three prison officers and an inmate were recovering in hospital today after a riot at Mountjoy jail.
Inmates used pool cues and balls to attack staff in a disturbance over access to the exercise yard.
Officers in riot gear were drafted in to bring the situation under control after 9.30pm.
It is understood that 74 prisoners were involved in a stand-off after forcing their way out to the exercise yard from A-wing and arming themselves with makeshift weapons.
Riot squad officers and dog handlers restored calm after about two and a half hours.