Police in the western city of Bielefeld say they've detained 52 people belonging to two biker gangs. Detectives believe the arrests prevented an imminent violent confrontation.
Police said they received intelligence that the "Hells Angels" and their adversaries the "Turkish Nomads" were preparing for major clashes in Bielefeld on Sunday.
Riot police and special forces officers took part in raids at several locations, initially leading to the arrests of 32 members of the rival biker gangs, known as Rockergruppen ("Rocker groups") in German.
Officers also seized typical weapons used on the biker scene, including knives and clubs, along with leather vests, officials said.
Police said the gangs arrived by motorbikes and cars from the Ruhr district and Rhineland, a large area of western Germany that borders the Netherlands, to take part in the violence.
Police were initially alerted to a convoy of 10 "Hells Angels" bikes on the A2 highway that runs into the southern end of the city from Dortmund. Later, police set up checkpoints on the highway and the nearby A33, they said.
Several other gang members were later arrested, taking the total to 52. At least seven people were taken into custody.
Many of those who had traveled to Bielefeld were sent home with a city-wide ban, German broadcaster WDR reported.
Biker gangs have long been an issue for German authorities, who have struggled to have the groups banned.
Earlier this year, police said they thought gang members were behind a shooting in Germany's financial capital Frankfurt.
Last December, police in the northern city of Hamburg arrested several suspected "Hells Angels" members after a shooting.
mm/kms (dpa, WDR)