Increasing tensions between rival loyalist factions led to fighting in which 12 men were injured at Portadown Football Club's social club. Local politicians have appealed for calm.
Violence broke out inside the Shamrock Park social club in the Co Armagh town on Monday afternoon. Police were also called later to Craigavon Area Hospital, where there was further trouble as the victims were awaiting treatment.
Two men who were seriously hurt in the clashes were said to be "stable" in hospital yesterday. Most of the injured were treated for upper body and head wounds.
Fighting broke out when a gang of men carrying baseball bats and pickaxe handles attacked drinkers near the end of an Irish League Premiership match in which Portadown beat neighbours Glenavon 2-0.
A DUP Assembly member, Mr Mervyn Carrick, said: "This had absolutely nothing to do with soccer, nothing to do with Portadown FC or Glenavon FC. It was hooligans and thugs who decided they would vent their spleen on one another and try to settle some old scores."
It is understood the violence broke out when UVF supporters attacked supporters of the rival Loyalist Volunteer Force who had earlier attended a memorial service for their murdered leader, Billy Wright, shot dead by the INLA two years ago.
There have been clashes between loyalists in the town in recent months. The RUC has had to keep the rival sides apart in hospital when the victims are being treated. Mr Carrick said: "There have been inter-factional tensions for some months now. They are vying for position and trying to assert their dominance over each other and in certain areas. There have been a number of previous, less publicised, clashes between these groups, but this one was clearly premeditated."
Meanwhile, a 17-year-old youth was shot in Ballynahinch, Co Down. He was treated in hospital for a bullet wound to the leg. His condition was described as "stable". The attack happened on Monday night at Willow Crescent, where the youth was confronted by three masked and armed men.