Achille Serra, Rome's chief of police has reacted angrily to Manchester United's suggestion that travelling fans face a "real danger" of attack whilst attending the Champions League quarter-final first leg against Roma. United are expecting 6000 fans to travel and advised fans to avoid certain areas in the Italian capital where they could be subject to attacks from "Ultras", the hard-core Roma hooligans.

"I am astonished but also worried by Manchester United's statements," said Serra. "There's no doubting the fact that there have been difficulties in managing law and order between English and Italian teams. "But it's the job of everybody to calm things down and lower tensions. A letter of this kind works in the opposite way, raises tension and risks provoking incidents."

Serra has already suspended the sale of alcohol to fans in the Italian capital from midday on Wednesday until three o'clock the following morning, and has been in talks with the British ambassador in Rome to assure him that "the number of officers who'll be on duty is proportional to the event."

"Rome is one of the safest cities in the world," he added. "Obviously, each team has small minorities of violent supporters, but to generalise or make this city out the way it has been in this letter is completely wrong and does not correspond to reality. Rome is a civil city. The places at risk, if there are any, will be under surveillance. But I do not accept that you cannot take the metro or go to some places in the city."

Three Middlesbrough fans were stabbed in Rome last year when rival fans clashed before a Uefa Cup match.