Eighteen Manchester United fans were hospitalized in Italy last night after crowd trouble at the club's Champions League clash with Roma.
The trouble broke out when Roma fans began taunting the 4,000-strong visiting support after the Italian side took the lead shortly before half-time.
Manchester United supporters retaliated by throwing missiles at the Italians and at riot police who waded in with batons to end the trouble.
Some of the English fans have accused the police of heavy-handedness and of striking people unnecessarily.
Roma fans also pelted the United support with missiles after the Premiership side equalised and after the final whistle, belfasttelegraph.co.uk reports.
The warning, posted on United's Web site earlier this week, instructed fans to avoid certain areas of the city and not to use the city's metro because "there is a real danger of being attacked by the 'Ultra' fans of AS Roma.''
Rome city officials were outraged by the warning, saying it would only excite tensions.
For Roma, the game is the biggest European contest since losing the 1984 European Cup final to Liverpool on penalties. The 70,000 tickets for Roma fans sold out in about half an hour last week, the AP reports.
Wayne Rooney finally broke his 18-game Champions League drought but there was very little else for 10-man Manchester United to cheer as their Treble hopes suffered a setback in the Stadio Olimpico.
Paul Scholes` dismissal for two yellow cards after just 33 minutes had left the Red Devils in trouble against Roma.
For a brief period after Rooney had coolly levelled Taddei`s first-half strike, it appeared United would complete their mission with spectacular success.
But substitute Mirko Vucinic bundled home the rebound after Edwin van der Sar had failed to hold Mancini`s blistering shot to earn Roma a richly-deserved victory.
At least Sir Alex Ferguson got the away goal he demanded but the United boss knows his side, lacking the suspended Scholes, will have to do better in the return leg on Tuesday to stand any chance of progressing to the last four.
Ferguson had promised every tactical angle would be covered as United attempted to reach the semi-finals for the first time since 2002, u.tv reports.
Prepared by Alexander Timoshik