The group were met by anti-racism protestors, who they have previously clashed with, as they charged through the Old Town in Sweden’s capital.
At least one police officer sustained injuries, and several people were taken away from the scenes in ambulances.
Police spokesperson Lars Bystom said that the exact number of detainees remains unclear, but guessed “we have suspended or removed 50”.
They added that they did not believe the Holocaust had happened, and that they considered Hitler to be a role model.
Some areas were also closed off, affecting traffic and public transport around the city.