PARIS (AP) _ The focus of soccer's biggest event moved from stadiums to police stations today as authorities in Marseille tried to stop violent clashes involving English fans.

On the sixth day of the World Cup, with the United States finally set to make its debut against European champion Germany in Paris, Marseille regional officials banned the sale of alcohol and corralled fans arriving for this afternoon's England-Tunisia game into hotels and holding areas. An estimated 12,000 English fans were expected.

At last count, 50 people had been arrested, at least 30 of then from England and a handful from Tunisia. The injury count stood at 37, including an English man who had his throat slashed.

As the fights raged Sunday, the soccer went on elsewhere, with ugly scenes of its own _ 123 fouls, a two-game ban for a wayward elbow and two lackluster 1-0 games.

The fights started Saturday and escalated Sunday when English and Tunisian fans started hurtling rocks, bottles and angry words at each other.

Today, police moved in reinforcements, expecting the worst.

``The fear is that the better-known ringleaders are still on their way to Marseille. The fact that they are coming so late proves that they are not interested in the football, only what comes after,'' said Keith Cooper, spokesman for the world soccer body FIFA. He called the troublemakers ``mindless perverts.''

The skirmishes in Marseille were fueled by drunkenness and insults. Shop windows were smashed, cars were overturned and innocent diners cowered in the scattered restaurants that dared stay open during the mess. English fans burned Tunisian flags while giving Nazi-like salutes.

``What can we do to combat these individuals?'' said Sepp Blatter, FIFA's newly elected president. ``We must get rid of them, stop them from entering stadiums and return them to their countries. Football is a game and must bring joy to the whole world.''

Some 1,900 policemen were patrolling Marseille, anticipating more violence, in part because as many as 2,000 English fans came to the city without tickets, hoping to find some on the black market.

``There won't be any trouble unless too many English are kept out of the stadium for a lack of seats,'' said Kevin Sharpe, who came from Southampton, England, with his brother. ``France should sell more tickets.''

The violence was condemned in England, but English Football Association security advisor Brian Hayes dismissed suggestions the country withdraw from the tournament.

``That's absolute rubbish,'' Hayes said. ``The England team have been training for years, they've qualified, they're here as of right. This is nothing to do with football, this is just sheer hooliganism and drunkenness.''

While fretting over the rampages in the streets, FIFA also dealt with a nasty on-field confrontation.

Dutch striker Patrick Kluivert was banned for two games for elbowing Belgium's Lorenzo Staelens in the chest during Saturday's 0-0 draw. Kluivert, who received a red card for the foul, will miss the Netherlands' other first-round games against South Korea and Mexico.

Kluivert, who is black, said he lashed out at Staelens after being ``deeply hurt'' by what he said were offensive comments by the Belgian defender.

``I pushed him,'' Kluivert said. ``I couldn't control my emotions.''

Sunday's games featured three teams making World Cup debuts and the level of play was about what would be expected of rookies.

Argentina beat Japan and Yugoslavia downed Iran, both 1-0. Croatia, as expected, easily handled Jamaica 3-1 in Lens, although the result did little to dampen the enthusiasm of thousands of green-black-and-yellow-clad Jamaican fans, who beat drums and danced before, during and after the game.

And, unlike the English, they caused no trouble.

``We're here to have fun,'' said Trevor Bird, who had driven from Amsterdam to watch his team. ``We know we won't win the World Cup. But we don't even have a professional league and we qualified. That's reason enough to celebrate.''

Mario Stanic, Robert Prosinecki and Davor Suker scored for Croatia and Robbie Earle connected for Jamaica in a game matching World Cup newcomers. Prosinecki also scored for Yugoslavia in the 1990 World Cup, before the breakup of the Balkan nation.

There were 60 fouls, including 35 from World Cup first-timer and 2002 co-host Japan, in Argentina's victory, which was decided by Gabriel Batistuta's 28th-minute goal in rainy conditions at Toulouse.

``There are things we can improve,'' Argentine captain Diego Simeone said. ``But the order of the day was to win, and we did.''

At Saint-Etienne, Sinisa Mihajlovic's 25-yard free kick in the 73rd minute gave Yugoslavia its victory in a game between two nations back in the World Cup following politically related absences.

Yugoslavia was banned from the 1994 tournament because of international sanctions, while Iran's once-formidable soccer program took a downturn after the 1979 Islamic revolution.

Next on the Iranians' schedule: a potentially tense showdown with the United States on Sunday.

``Our mission at the World Cup is not over with this loss,'' Iranian coach Jalal Talebi said. ``We will fight on. ... We are looking forward to a victory against the United States.''