Two prisoners, one armed with a weapon, barricaded themselves in a cell.
A five hour hostage crisis at a prison ended during the week after a weapon was exchanged for a bar of chocolate.
The incident happened at around 3pm on Thursday at the Midlands Prison in Portlaoise.
Two prisoners, one armed with a weapon, barricaded themselves in a cell after taking another hostage.
Specialist officers were called in along with trained negotiators.
After a five hour standoff, one of the prisoners agreed to open the cell and exchange the weapon for a mars bar.
The hostage was left uninjured and the attackers were detained by prison officers.
Meanwhile, the Irish Prison Service has confirmed an incident happened in the Midlands Prison on Thursday, involving four prisoners.
It says it was successfully resolved and no staff were injured, while the prisoners involved received only minor injuries.
Senior Management in the jail have started an investigation and gardai were notified.