Police and football officials are preparing for fresh outbreaks of violence at next month's Euro 2000 Championship in Holland and Belgium following the clashes between English and Turkish supporters that marred the UEFA Cup final in Copenhagen on Wednesday night.

The British National Criminal Intelligence Service (NCIS) yesterday warned that hooliganism was again on the increase, and predicted that English fans were "almost guaranteed" to be involved in any trouble in Holland and Belgium.

In the worst outbreak of widespread football-related violence since England supporters went on the rampage during the 1998 World Cup, 19 people were injured and more than 60 arrested in clashes between supporters of Arsenal and Galatasaray .

Last night there were reports of fresh fighting between the supporters at Copenhagen airport. Bottles were thrown and fights broke out between the rival factions as fans waited to board planes home, a Danish police spokesman said.

Earlier, 15 Britons arrested during the troubles were released without being charged. Danish police said their priority was to get the fans out of the country as quickly as possible. But this was condemned by British authorities, who said hooligans causing trouble abroad should be put through the judicial process as a deterrent.

Mark Steels, a spokesman for NCIS, which shares intelligence on hooligans with police forces in Britain and outside it, said the organisation was not surprised by the violence in Copenhagen. He said that statistics for this season, due out in August, will show hooliganism has risen, particularly violent confrontations away from grounds and between supporters of non-Premiership clubs.

Police have also recorded a significant rise in the number of weapons being used this season. "We are talking about people with iron bars, sticks, knives," said an NCIS spokesman. It is very vicious. These people are not deterred by legislation. They are a new generation."

Attention will now switch to Euro 2000, which is being co-hosted by Belgium and Holland. Steels said: "I don't think people can say any more that this sort of thing won't happen in Euro 2000. We have fears about the security of the tournament, full stop. I'm afraid to say that we have fears wherever English fans go at club level and quite often, indeed more often, at international level.

"We fear that English fans are going to cause trouble at Euro 2000, and I can almost guarantee you that if there is any trouble at Euro 2000, English fans will be part of it."

Wednesday's violence was the latest in a series of clashes between English and Turkish fans since two Leeds supporters were murdered in Istanbul on the eve of the club's semi-final first leg tie against Galatasaray. On Tuesday, Arsenal fan Paul Dineen was stabbed in the back in Copenhagen.

Many Arsenal fans arriving at Luton airport yesterday said a rivalry had been established between the two countries' hooligans which would carry on this summer. Both sets of supporters could be in Holland at roughly the same time and the teams could meet in the quarter-finals on June 24th.

The British authorities are hoping that police in Belgium and Holland, who have been co-operating with NCIS in the run-up to the tournament, will have learned from Wednesday. Despite warnings that Arsenal hooligans were planning to travel to the match, Danish police adopted a "softly softly" approach. British police yesterday refused to condemn the tactics employed, but privately they believe the Danish police adopted a low key approach because it worked for the 1998 Cup Winners' Cup Final involving Chelsea.

However, the organisers of Euro 2000 yesterday insisted they were well prepared. A spokesman, Jan de Grave, said: "We cannot guarantee a 100 per cent safe tournament but we are confident we've had the right preparation."

David Davies, the English FA's executive director, said a meeting with the Turkish FA had been brought forward in an attempt to "restore the normal relationship between the two footballing nations".

Davies offered an apology to the people of Copenhagen for the recent violence. But he was adamant that England's 2006 World Cup bid would not be harmed. Meanwhile brawls and gunfire left two dead and 22 injured as fans in Turkey celebrated Galatasaray's win. A 22-year-old man was stabbed to death and another was injured in a melee and a one-year-old girl died of a head injury she sustained from a ricocheting bullet as fans fired shots into the air.