The tournament's organizers wrote on their website that they couldn't guarantee a safe environment and were thus canceling the Saturday event.
Both fans and the police were injured in the brawl, although precise numbers were unavailable.
The incident started around 7 p.m. when fans of VfB Lübeck and FC St. Pauli got involved in a huge confrontation that turned violent. There were some 200 police officers involved in trying to separate the two sides.
At first the football match continued, but in the second half, the clashes became so hefty that spectators began leaving the stadium and the match was halted. It took several hours to get the situation under control.
“We had a situation in which a large number of very aggressive FC St. Pauli fans continued to seek out confrontations throughout the entire stadium, including with the police,” Robert Golz, the match operations director told Sky Sport News. Police used clubs and tear gas to get the situation under control, he said, adding a number of people “not involved (with the rioting) were injured from pepper spray."
An eye witness said, “It was at times very intense, how children and their parents didn't know where they should go. We weren't supposed to go either outside or upstairs and everywhere people were running. It was quite shocking."