Several of the people injured in a knife attack at the Oxegen Festival at Punchestown are believed to be from Derry.
The attack happened in the early hours of yesterday at one of three large campsites at the music festival.
Five teenagers were treated for their injuries when they were attacked with a Stanley knife.
Four of the men were treated on site for their injuries, while a fifth required treatment in hospital.
The incident happened at around 4am yesterday and festival goers reported being woken around an hour later by Gardai seeking witnesses.
Four of the five victims were from the North of the border and their families were all informed of their injuries.
Almost 85,000 people are expected to attend the Oxegen Festival this weekend.
A spokesman for the Gardai said: “Gardai are investigating an incident which occurred shortly after 4am on the 9th of July 2011.
“Five men in their late teens were injured following an assault at the Blue Campsite at the Oxegen Festival, Punchestown.
“Four of the men were treated for their injuries on the site and one man, aged 19 years, was removed to Tallaght General Hospital.
The men are believed to have received slash wounds.
“The families of the injured men have been notified, as appropriate.”