Two prisoners who climbed on top of roof at Cloverhill Prison on Wednesday as part of a protest came down voluntarily at about 1.30am on Thursday morning.
The two men climbed on top of a three-storey accommodation building and refused to come down after an estimated 60-strong group refused to leave an exercise yard and return to their cells at the prison.
Gardaí have launched a criminal investigation into the disturbance that saw at least one prisoner, who is believed to be an asylum seeker, held hostage and seriously assaulted and 10 others injured and hospitalised.
It is understood one of the inmates injured in the incident remained in hospital on Thursday morning.
Disciplinary hearings for prisoners involved in the disturbance will commence on Thursday morning, according to the Irish Prison Service. A major debriefing operation for staff members is also due to take place.
Separate to the Garda investigation, the events will also be subject to an internal prison service inquiry.
The Irish Penal Reform Trust (IPRT) has called for an "independent, effective and prompt investigation" into the circumstances of the incident, including any force by prison staff.
The IPRT noted that poor conditions and overcrowding were “unacceptable for both prisoners and prison staff” and were a contributing factor in the tensions which can place both groups at risk.
It is still unclear what the protests were about, but some staff believed they were taking issue with “the general conditions”.
The disturbance at Cloverhill Prison was brought to an end by staff in riot gear on Wednesday evening after the governor of Cloverhill, Ronan Maher, ordered its riot trained officers, known as control and restraint teams, to move into the yard to remove the ringleaders of the protest after at least four hours of talks.
The order was made after a prisoner, who was being held hostage, was set upon by a group of others.The prisoner was beaten and suffered a broken arm before being slashed in the face with a shiv, or makeshift knife.
Security sources said one of the leaders is in prison serving sentences for violent crime. He is a member of a notorious crime family and had previously been involved in extreme violence, including in the prison setting.
Trouble flared when an estimated 60 prisoners taking a recreational break in the exercise yard in the B division of the jail refused to leave and return to their cells.
It is understood goalposts in an area next to the prison’s B division were ripped from the ground and smashed before being used to rip down razor wire and clear access to a roof. They were also used as makeshift weapons when riot squad officers were called in to restore order after several hours of negotiations failed.
During the protest some prisoners in the yard vandalised prison infrastructure and a security and observation hut in the yard was destroyed.
When the prison service’s riot squad was ordered into the yard, the group of 10 to 15 ring leaders refused to move and their compliance was forced. In the course of clearing the yard, 10 prisoners were injured.
A statement from the Irish Prison Service said the control and restraint teams had only been deployed when efforts to negotiate a peaceful end to the disturbance were not successful.
