Rome Mayor Walter Veltroni has blasted Manchester United for telling fans they risk being attacked here ahead of Wednesday's Champions League clash with AS Roma.
The English club advised its fans to avoid certain bus, road and train routes and parts of the city and warned them not to travel independently to the game.
"There is a real danger of being attacked by the 'Ultra' fans of AS Roma," read a statement on Manchester United's website.
Veltroni does not agree.
"Rome is a city that has always welcomed all those who come in a hospitable way," he said Tuesday.
"I consider what appeared on the Manchester United website to be an unpleasant accident, but it is also dangerous because it threatens to feed a negative climate".
Rome Prefect Achille Serra said he was "astonished" by the Manchester United statement.
"There is no doubt that there have always been problems in controlling order and security at matches between English and Italian clubs," Serra said.
"But it is everyone's job to tone things down. A letter like this does the opposite and threatens to cause incidents".
Serra stressed that Rome is one of the safest cities in the world.
He admitted that "every team has small elements of violent fans", but argued that the English club's statement blew things out of proportion and gave the wrong impression.
Roma coach Luciano Spalletti showed irritation too in Tuesday's pre-match press conference.
"Manchester United should have done their research better," Spalletti said.
"It annoys me to hear people say our fans are violent. I've been here for two years and I have seen that they are passionate, but well-behaved.
"The right thing to do would be to laugh it off, but it is important to highlight that they have implied something serious".
Manchester United coach Alex Ferguson, meanwhile, sought to soothe things over.
He said Rome was not a dangerous place and explained that such warnings are standard practice for away games.
In recent years hooliganism has been a recurring problem for Italian soccer. The game here is still trying to recover from the death of a police officer in rioting at a top-flight match in February.
The Manchester United statement singled out Piazza Campo dei Fiori, one of Rome's hottest areas for nightlife, as a potential trouble spot.
Three Middlesbrough supporters were stabbed during fights with Roma's hardcore fans in the area before last year's UEFA Cup quarter-final.
Some 6,000 Manchester United fans are expected to come to the Italian capital for Wednesday's Champions League quarter-final first leg, around 1,000 without tickets.
Many Red Devil supporters are already here. And they do not seem worried about the threat of violence.
"We accept the advice, but we aren't afraid to walk around the streets of Rome," one fan said Tuesday.
"The important thing is to ignore provocation. We are here to enjoy the match and the beauty of the Eternal City".
The Rome authorities have banned the sale of carry-out alcohol from midday Wednesday until 3am Thursday to prevent drunkenness-related violence, although it will be possible to have a drink in the city's bars, restaurants and cafes.
The police also intend to keep the English fans in the stadium for 90 minutes after the end of the match to prevent clashes with Roma supporters.
The calls for calm did not stop the two clubs' coaches sparring about the merits of their star players Tuesday.
Ferguson said United's Portuguese talent Cristiano Ronaldo is the best player in the world at the moment, while Francesco Totti is merely "one of Roma's best".
Spalletti replied that he is "more than happy to keep Totti".
