A riot by motor rally fans in Killarney early on Sunday morning resulted in 25 arrests and seven people from outside the area are to appear in court this week.
Gardai called to investigate an assault in New Street at 1.45 a.m. as crowds began to leave discos and bars were charged by a crowd of 500 people who, the gardai said, were "very intoxicated".
The crowd threw bottles, cans, stones and "every kind of missile they could lay their hands on", and windows were broken.
Eyewitnesses say the situation was very frightening, with repeated charges on gardai.
Gardai donned riot gear to control what eyewitnesses described as "something like you'd see in Northern Ireland" and back-up units were called in from outlying areas.
Afterwards gardai said the problem was contained before it got out of hand - by 3.15 a.m. the crowd had dispersed - but it was a "really frightening situation and one we have never experienced in Killarney before".
The Ordnance Survey Rally of the Lakes drew huge crowds from Northern Ireland, Britain and all of the 26 counties. It was the first international rally since what gardai yesterday described as "a similar situation" in Salthill, Co Galway, last year, which resulted in the cancellation of the annual rally there in February.
Supt Michael Maher said a strong Garda presence, with support from the Garda helicopter during the rally, had kept order up to that point. The riot was "a nasty situation" for which gardai were prepared, he said.
The rally organisers said the riot had nothing to do with the rally, which they said had gone extremely well.