Manchester City have taken the dramatic step of writing to supporters travelling to Italy for next week's Champions League match to urge them not to wear club shirts or scarves.

City take on Napoli, where visiting supporters have previously been subjected to knife attacks. In a letter to the fans who bought tickets for the match, club officials have also urged them to avoid no-go areas, including the railway station and the Old Centre of the city.

It is the first time City have issued such advice. The move comes after four Bayern Munich supporters were slashed with knives outside the Stadio San Paolo before a Champions League match last month. There were numerous reports of knife-wielding thugs on mopeds carrying out vicious assaults and two more German fans were stabbed in the city centre.

Last year three Liverpool fans were knifed, with two taken to hospital, when they visited Naples in the Europa League. Worried Manchester City officials drew up the advice after meeting officials from police at home and in Italy.

City's letter, signed by the operations manager Steve Sayer, says fans should "take care and use common sense" and "travel in groups where possible".

It says the club is "confident that there is a low risk of problems" but adds: "We would also advise against wearing club colours away from the game, particularly when taking public transport."

Tensions around the televised encounter are set to be high as defeat could see the Italians knocked out of the tournament. No alcohol will be served inside the ground and City supporters will be locked in after the final whistle for 45 minutes.

City said they had been working closely with the British consulate in Naples, Napoli and the Italian police to ensure the safety of their fans. The Premier League club are second in Group A, with seven points, behind Bayern Munich on 10 and ahead of Napoli with five.