Three Irish football fans were among 14 people arrested in Poznan, Poland in the early hours of this morning after a flareup of violence believed to have been sparked by domestic hooligans.
The town's mayor confirmed the arrests in the town's old square after riot police moved in to deal with clashes around 1am.
Reports said the trouble ignited after masked men believed to be Polish football fans entered the Stary Rynek square and targeted Irish and Croatian supporters that until then had been sitting at the pavement terrace of the Sami Swoj pub.
Witnesses said the trouble was brief but violent.
"It was mental, one minute we were drinking beer and having a really great time," said Ireland fan John O'Rourke, 34.
"The next we were running for our lives,"
Local Michal Smyla was caught up in the violence when the table he was sitting at was suddenly surrounded.
"I was with friends having a beer when some guy in a mask and a hood grabbed me by the neck and punched me," he said.
"And then all hell broke loose."
A press photographer at the scene reporting seeing several other people with bloody injuries.
"One man seem to be unconscious and was being dragged into safety into the nearby pub the Piwo Napieciwko," the photographer, who did not wish to be named, said.
"Pub staff gave first aid to those that were bought inside. It seemed as if they were particularly targeting the foreign fans especially the Croatians."
He said that riot police arrived within 10 minutes, dispersing the crowd and extinguishing the blazes that started in litter bins from flares. Most of the alleged perpetrators had dispersed before police arrived.
Witnesses posting on Twitter said the violence appeared to have been orchestrated by fans of local club Lech Poznan.
Irish fan in Pozna Kevin Daly said it appared to have been a premeditated attack by Lech ultras on rivals attached to Dynamo Zagreb, with Irish fans caught in the middle.
@Danbyrne90 huge organised hooligan fight between lech Poznan fans afaik. Was right there. Was hardcore. glad to not be in the middle!— Kevin Daly (@KevinDaly09) June 10, 2012
All trouble in Poznan started&ended by polish.Riot police doing their jobs contrary to what lots if irish thought was an invasion. #Euro2012— Kevin Daly (@KevinDaly09) June 10, 2012
Local police said that as a result of the incident they had made 14 arrests, and investigations were continuing. Those arrested included 10 Polish, three Irish fans and one Croatian.
Poznan Mayor Ryszard Gorobelny today described the trouble as a minor incident, adding that some 47,000 supporters had attended the town's fan zone yesterday with no arrests.
Up to 30,000 Irish fans are believed to be in the town ahead of tonight's opening group game against Croatia.