ROME — An American and Manchester United fan were hospitalized after being stabbed today ahead of the Champions League final. Nine people, including United and Barcelona supporters, were arrested.

Four Italians were arrested in Ostia, on the coast near Rome, after they attacked an American, apparently mistaking him for a United supporter. The man was beaten up and stabbed in his thigh and backside, police said.

A United fan was taken to a hospital after he was stabbed in the thigh, police said. The fan reported that he had been attacked by four people near his hotel in the Vatican area.

Up to 50,000 United and Barcelona supporters converged on Rome for the match Wednesday night, and large numbers of police patrolled the city.

Three Barcelona fans were arrested after police searched their car and found blunt objects, including clubs and a javelin, police said. They were traveling from Civitavecchia, a port near Rome where hundreds of Spanish fans had arrived by ship.

Two United fans were arrested for assaulting bystanders and police in Campo de Fiori, a historic piazza and popular tourist hangout. Police said the men were drunk despite a ban on alcohol sales imposed by authorities in areas including the city center and near the stadium.

Hundreds attended Pope Benedict XVI's public audience at the Vatican, waving their flags and scarves before the pontiff. The match referee, Massimo Busacca of Switzerland, greeted the pope at the end of the audience.

Some 67,000 people are expected to pack the Stadio Olimpico for the match. VIPs include the Spanish royals and Britain's Prince William, who was invited by the English Football Association as the organization's president.