UEFA have threatened to switch the destination of the 2009 Champions League final from Roma if any violent incidents occur at Tuesday's quarter-final between AS Roma and Manchester United. Manchester United's last two visits to Rome witnessed a lot of violent incidents and many fans were stabbed and seriously injured. “If tomorrow at Roma-Manchester United, incidents are proved to have happened outside the stadium which are like those at the match with Real - with people stabbed - we would have to reconsider the decision to assign the 2009 Champions League final to Rome,” UEFA spokesman William Gaillard told Italian radio, according to ANSA news service. Roma's knockout game with Real Madrid, 2-1, last month was also blighted by violence. The Italian police have denied all the permits to sell alcohol before the game in attempt to avoid any crowd brawl.