French authorities fear they may not have seen the end of World Cup violence, and that the worst might be yet to come. They worry most about a confrontation between English and German hooligans.

So far, English and German fans have been kept apart as their teams played at different venues. But hooligans from both countries nevertheless have run amok.The newspaper Le Monde on Thursday cited an intelligence memo saying German extremists plan to travel to Lens in northern France for England's game with Colombia on Friday. The goal: "to combat the English enemy and try to gain the title of `best hooligans of Europe.' "

The interior ministry had no immediate comment on the newspaper report.

A Lens spokeswoman, Isabelle Isaert, insisted "the kids got the message" when officials jailed several Germans after rioting on Sunday. Three were quickly sentenced to a year in prison.

But a ministry source privately confirmed the hundreds of police to be deployed for the match were alerted about the possibility of German-English clashes.

Violence has shaken and tainted the five-week soccer championship, with clashes outside stadiums leaving more than 100 injured, a policeman in a coma and an English fan in critical condition.