Tánaiste Simon Coveney has condemned a missile attack on a migrant detention centre in Libya.
The Tajoura centre, located east of the capital Tripoli, was hit at around midnight on Tuesday.
The UN Refugee Agency (UNHCR) and the International Organization for Migration (IOM) have called for a "full and independent investigation" to determine how it happened and who was responsible.
The airstrike has left at least 44 people dead and dozens injured.
"Such an attack deserves more than condemnation," both agencies added, in an appeal for a probe "to determine how this happened and who was responsible, and to bring those individuals to account".
According to one report, a cell was hit containing more than 120 people.
Most of the detainees in the centre are from Mali, Nigeria, Ivory Coast, Bangladesh, Morocco and Tunisia.
UN Secretary-General António Guterres said he was "outraged" by reports of the attack.
He also called for an independent investigation of the circumstances of the incident, to ensure that the perpetrators are brought to justice.
The UN says the coordinates of the facility had been given to the parties involved in the conflict, and indicated the airstrike could amount to a war crime.
The International Red Cross says it is supporting medical facilities treating the wounded.
It is providing surgical sets, surgical gloves, infusion sets and dressing kits to Tajoura Field Hospital, where the majority of the wounded have been treated.
It is also providing body bags to the Tripoli Medical Centre Morgue.
Speaking from Germany, Mr Coveney said: "I condemn the missile attack on a Libyan detention centre in Tajoura... which has killed dozens of migrants and refugees, and injured many more.
"I join the calls of the EU and the UN for an investigation into this attack, and call on all parties to allow unconditional access of humanitarian actors.
"Attacks on civilians, or reckless attacks which endanger them, are completely unacceptable, are contrary to international humanitarian law, and in this instance may well constitute a war crime.
"This tragic event underlines the fact that the system of detention centres in Libya is completely unsuitable for migrants, and puts them at risk.