Uefa rebukes Chelsea coach over Frisk

Chelsea last night challenged Uefa to prove that it was their fans who made the death threats that forced the referee Anders Frisk to quit. The club will also strike back today at allegations from Europe's referees that their manager, Jose Mourinho, is "an enemy to football".

With outrage over Frisk's resignation growing yesterday, the Premiership leaders moved to defend their reputation over allegations that it was Chelsea fans who put pressure on the Swedish referee to quit. The threats were alleged to have been made as a result of the fierce criticisms levelled at the referee by Mourinho following their first leg defeat to Barcelona in the Nou Camp last month.

The stakes were raised on Sunday when Volker Roth, the chairman of Uefa's referee's committee, said that Mourinho was an "enemy of football" for his attack on Frisk. Chelsea are expected to release a further statement today that rebuts those charges.

Chelsea have promised to take action against any fan who is proved to have made the threats against Frisk. In a statement the club said: "We would like to make it absolutely clear that both the club as a whole, and our manager and first-team coach Jose Mourinho, condemn any threats made to Mr Frisk, his family or friends which may have, in any way, influenced his decision to retire as a referee.

"If there is any evidence of such behaviour by Chelsea fans then we would totally disassociate ourselves from them and we would welcome any such evidence to be passed to us so we can investigate and take the appropriate action."

Mourinho invited controversy when he alleged that Frisk had a conversation with the Barcelona coach Frank Rijkaard in the referee's room in the Nou Camp at half-time in their Champions' League first leg defeat. Before Chelsea beat the Catalan side 4-2 in London last week, Mourinho said again that the referee had "helped" Barcelona".

Yesterday Roth said that referees may have to strike if the pressure became intolerable: "We cannot just do nothing," he told Germany's Bild newspaper. "There will be a demonstration of solidarity among the referees as you have never seen before. I am really no friend of strikes but we must consider measures.

"Of course, we make mistakes like every player and coach. But that shouldn't lead to referees being sworn at or even threatened. But if things escalate and millimetre decisions, which can only be decided after three slow motion replays, trigger exaggerated reactions, then the possibility exists that even the best referees in the world will abruptly give up."

The Uefa spokesman, William Gaillard, said yesterday that the governing body were still hopeful of persuading Frisk to change his mind about his decision to retire. "Our first reaction was of solidarity and compassion," Gaillard said. "I think people should keep in mind that these are not highly paid people, they're not like the players or the coaches. These are people who are basically amateurs, who also have another job on the side and it is quite unfair to put them in the situation where they have to go into hiding."