Police are bracing themselves for Chelsea's trip to Cardiff on Sunday with a specialised plan amid fears of clashes between supporters.
Newspaper reports say that South Wales Police have contacted establishments in Cardiff informing them that the risk category for Sunday's game, which is live on Sky Sports, has been increased.
A large-scale fight took place between rival supporters of the two clubs after an FA Cup tie at Stamford Bridge in 2010.
Approximately 3,000 Chelsea fans are expected to travel to the Welsh capital for the game.
"South Wales Police have been working closely with colleagues from the Metropolitan Police, British Transport Police, partner agencies and officials from both clubs in preparation for the Cardiff City vs Chelsea FC match," a South Wales Police spokesperson told Sky Sports News.
"We don't comment on specific numbers of resources allocated to individual events, however, we have developed a specific policing plan with dedicated resources.
"We are committed to facilitating a safe and enjoyable environment for everyone, however, we will deal swiftly and robustly with anyone who attempts to disrupt this."