Tánaiste Eamon Gilmore has appealed for space for the families of a woman killed after a concert in Japan and her friend who was also sexually assaulted.
Two men from the US, named in local media reports in Tokyo as 19-year-old backing musician Larry Perry and hip-hop dancer James Blackston (aged 23) are being detained on suspicion of sex attacks.
Nicola Furlong, 21, was found unconscious at an upmarket hotel and later died.
The Tánaiste, also Minister for Foreign Affairs, offered his sympathies to the Furlong family from Curracloe, Co Wexford and to the family of the dead woman's friend, also from Wexford.
"I want to offer my deepest condolences to the Furlong family who have lost Nicola in such awful circumstances," he said.
"There is a police investigation under way and my department and the Irish Embassy in Tokyo are continuing to provide consular assistance to Nicola's family and to Nicola's friend who was also a victim in this case."
The two men are held on suspicion of a quasi-forcible indecency, according to Japanese police.
Both women were studying Japanese and business at Dublin City University and were in Japan on a studying trip.
The Tánaiste asked for space for both families to deal with the incident after last Wednesday's concert.
"The parents of both women have appealed to the media to respect their families' privacy," he said.
"I would respectfully ask the media to bear that in mind in their reporting of the case and to allow the families and friends of both women privacy at this very difficult time."
According to reports from Japan, police are investigating whether the two men approached the women after the concert and invited them to dinner.
It has been reported that witnesses saw the women being pushed into a taxi in central Tokyo on Wednesday night and that investigations centre on whether the women were drugged before they were assaulted.
Ms Furlong's body is to be repatriated later this week.
Diplomatic staff are said to be liaising closely with the families of the two women since the incident.
The Tánaiste added: "My department continues to provide consular assistance to the two families and our embassy in Tokyo will remain in close contact with the relevant Japanese authorities as the investigation proceeds."