A detainee at Oberstown detention centre had to be treated in hospital after an incident with another detainee in Dublin last night.
A number of staff also required medical treatment.
Three members of staff were injured as they intervened in a incident involving two detainees last night.
One of the detainees and the three staff had to be treated in hospital - but they have since been discharged.
Management at the children's detention centre have confirmed the incident has been referred to the gardaí for investigation.
They have also begun arranging support services for detainees and staff.
It is the second such incident at the detention centre in a week.
It came after two female members of staff were injured when they intervened in a row between two detainees last weekend.
