Due to a major police operation, several streets in downtown Dortmund were closed on Sunday.
There was a physical altercation, said a police spokeswoman in the early evening without giving details.
“We are on site with strong forces.” The police asked bystanders to avoid the area around Rheinische Strasse near Heinrichstrasse.
Dortmund - There are traffic obstructions.
The background to the dispute is the subject of ongoing investigations.
dpa