More than 400 people were arrested in Germany after clashes around the World Cup match between the host nation and Poland, police have said.
The game had been identified as a potential source of trouble
All but three were released after a night in cells, but more than 100 face further investigation.
Police said trouble flared ahead of the match, as they tried to arrest "violent hooligans in the city centre".
A central square was sealed off and bottles were thrown at police in the worst trouble so far at the World Cup.
A police officer and 32 fans were injured in the clashes.
However, authorities said a pre-emptive operation to arrest "problem fans" before the game had been "successful".
About 60 known Polish hooligans were arrested during the day, after being spotted by Polish police working alongside German officers.
The match - which Germany won 1-0 - had long been identified as a potential source of trouble, with the two countries' wartime past and a recent history of football-related violence thought likely to stoke tensions.
Dortmund police said there had been 429 arrests in total, including 119 from Poland and 278 Germans.
The three still in custody are expected to be released later in the day. Another 115 will be investigated further, mostly for theft and bodily harm.
German fans did their best to help this Polish fan, hurt in clashes
Commissioner Hans Schulze said about 100 of those arrested were believed to be hooligans. The remainder were fans who had drunk too much.
He said that while the pre-emptive operation had been successful he could not guarantee that hooligans would not return.
"We hope it won't happen because we were very [quick to act] today and I think that's quite a good signal - even for the hooligans - not to come again to Dortmund," he said.
About two hours before the evening match kicked off, the festive mood in the sunshine in Dortmund's central Alter Markt square turned dark when German skinheads wearing black T-shirts began to behave threateningly, a police spokesman told Reuters.
"Their tone had become very aggressive so we decided to move in to prevent the situation from escalating," said spokeswoman Saskia Schneider.
German and Polish hooligans have a history of violence
"This situation led to attacks on the police. Then it spilled over and different fan groups started attacking each other."
About 120 fans threw fireworks, bottles and chairs at police.
Riot police sealed off the square, isolating the violent fans, before moving in to remove them.
There were thought to be about 7,000 Poles at the match. Poland are out of the competition.
Thousands more Poles made the trip to Dortmund without match tickets, but most are thought to have returned to home after the game.