German fans pelted police with beer bottles, fireworks and the chairs and tables from restaurants near Dortmund's Alter Markt, according to a Reuters eyewitness.

In separate clashes nearby smaller groups of drunken German and Polish fans set on each other, police said.

A Reuters TV cameraman suffered slight injuries after he was punched in the back of the head during the violence.

The police said some people had been injured by missiles, but none of them were badly hurt. They added that fan held in custody would be released in stages while others would face charges.

"Expectations of trouble proved self-fulfilling and made things very difficult for police," said Dortmund police chief Hans Schulze.

"We needed people on almost every corner today as the potential for aggression was so high... there was not a good mood in Dortmund today," he added.

Hundreds of riot police closed off the Alter Markt in the early evening after police spotted known German hooligans who were behaving increasingly aggressively. They then moved in to take about 100 people away.

Police had earlier detained about 70 Polish fans known to authorities as 'problem fans', some armed with metal batons and other dangerous objects.

At first the mood in Dortmund was largely friendly with noisy supporters drinking beer in the sunshine, but it turned darker as a group of German skinheads wearing black T-shirts and drinking on the Alter Markt began to behave threateningly.

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"What surprised us was the sheer number of fans who showed themselves ready to turn aggressive," said Schulze, adding that of the 300 people detained about 120-130 were known hooligans.

"We had hooligans here but they did not attack each other. Rather we had extremely drunk fans who set on police and then on each other."

Tens of thousands of Germany [Images] and Poland supporters descended on the western German city to watch their teams in the match, but for months the game has prompted fears of fan violence.

Last November about 100 German and Polish supporters brawled near the border.

Earlier on Wednesday, one group of German fans greeted their neighbours with the Hitler [Images] salute -- a criminal offence in the host country.

The relationship between the two countries, and especially the soccer fans, has been tense and marred by history as Poland suffered greatly under German occupation in World War II.

Additional reporting: Karin Strohecker in Berlin