Police in riot gear clashed with Manchester United fans during a Champions League match with AS Roma on Wednesday.

The clashes began shortly before halftime in the section of Stadio Olimpico where the 4,500 United fans were sitting.

Police hit fans with night sticks to restore order. The problems apparently began when opposing fans taunted each other following a Roma goal by banging on the partition separating the sections. The fans were also throwing objects at each other.

One fan was seen lying in the stands with blood all over his face.

Police removed three United fans from the stands in handcuffs, according to the Italian news agency ANSA.

Before the game, 18 United fans were injured in clashes with Roma supporters outside the stadium, and one fan was taken to a hospital in serious condition due to a knife wound to the neck, according to ANSA.

Tensions were high following a violence warning that United issued to the 4,500 English fans traveling to the game at Stadio Olimpico.

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.