Sixty-seven people were arrested during clashes between right-wing and anti-fascist protesters and police as a demonstration brought a town centre to a standstill on Saturday.
Police condemned the violence in Bolton, Lancashire, during which protesters attacked police officers and injured members of the public.
Thousands of people took part in a rally in Victoria Square, organised by controversial right-wing group The English Defence League (EDL), which campaigns against "militant Islam".
Police said protesters from Unite Against Fascism (UAF), who organised a counter-demonstration, were responsible for most of the violence.
Of those arrested, at least 55 were from UAF and nine from the EDL, police said.
