A large number of prisoners were forcibly removed from Mountjoy Prison after a violent protest by over 40 inmates.
They wrecked several cells, removing sinks and breaking televisions, last Thursday afternoon when they were refused access to their landing area because of a shortage of staff.
There has been heightened tension all week in Mountjoy following the murder of 34-year-old prisoner Robert O'Connor.
It is understood the staff shortage was caused by a number of members being on annual leave - plus staff who witnessed and tried to stop the vicious attack by four other prisoners on O'Connor are also on leave.
The incident happened in the Delta 2, D wing of the prison. Between 40 to 45 inmates housed there started wrecking the cells after they were informed they would not be let out into the landings.
Squads of prison officers then went in and forcibly removed up to 20 different individual prisoners involved in the trouble. They were then put into separate prison vehicles and moved to other jails around the country.
The operation lasted several hours. No staff were injured or hurt.
The Irish Prison Service confirmed a disturbance took place in Mountjoy last Thursday afternoon and some of the cells damaged.
“The matter was dealt with swiftly and professionally by prison management and staff”, a spokesman said.
A prison source said: "The inmates in the wing flipped when they heard they had not been given access to the landing.
"We don't know whether the protest was premeditated or just a reaction. It started in one cell and spread to the rest.
"They were all curtailed to the cells and they never got any further. They broke sinks, furniture and televisions.
"We decided to then remove most of the individuals causing the trouble and send them to other prisons.
"This is the usual procedure. Being sent to another jail is a form of punishment because they are removed from their friends for about a month and don't see visitors.
"There was nothing we could do about the staffing issue, it was just one of those things."
Each of the four suspects involved in Robert O'Connor's murder are being held in isolation in Mountjoy. Gardai have not interviewed any of them yet.
All the clothing they were wearing at the time of the attack last Friday has been removed for forensic examination.
Robert O'Connor had only been sentenced to six and a half weeks' jail for possession of a loaded pistol 48 hours before the vicious attack. He was regarded as a "gun for hire" in Mountjoy.
Neither gardai nor the prison authorities have established a motive for the attack so far.
The last murder in an Irish jail occurred in Cork in 2015, when one prisoner killed another in the kitchen.
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