Bayern Munich have condemned supporters who attacked police officers as they attempted to deal with fans who had used flares in the away section during Saturday's game at Hertha Berlin.
German news agency dpa reported that both Bayern and Hertha fans attacked police who tried to take down personal information from two Munich supporters after the use of pyrotechnics during Bayern's 2-0 win at the Olympiastadion.
The report said 27 people were detained temporarily after the clashes, which left six police officers injured, and face charges of breach of the peace.
In a press release on Sunday, Bayern condemned those responsible.
"FC Bayern want to clearly distance themselves from any supporters willing to use violence," Bayern executive Jan-Christian Dreesen said on the club's official website.
"Violence cannot and never should be tolerated. In line with Hertha BSC and the local authorities, FC Bayern will take action against the perpetrators of violence."
Flares are not permitted at stadiums in Germany, although fans around the country regularly chant that the use of pyrotechnics is "not a crime."
Those using flares at games can be issued with stadium bans if police are able to collect their personal information or they are identified by stadium security through video evidence.
In another incident involving fans from both clubs, a 35-year-old man was put in an artificial coma on Saturday, local TV network RBB reported.
The man was said to have tried to intervene in a brawl between Hertha and Bayern fans at a local train station and fell onto the tracks, sustaining severe head injuries.