Fifty five people were arrested and several people injured after violent clashes broke out between right-wing and anti fascist extremists and police during a demonstration in a town centre.
Controversial right-wing group The English Defence League (EDL) organised the rally in Victoria Square, Bolton, Lancashire.
A counter-demonstration by Unite Against Fascism (UAF) is also being held, and hundreds of police officers are battling to keep control of the rival groups.
Around 4,000 protesters descended on the town, with roughly equal numbers in both camps.
The two factions were meant to stay within two designated areas in the square, separated by steel barriers.
But a large number of protesters "intent on causing disorder" broke away from the protest site, police said.
Two members of the public were injured by protesters and taken to a nearby shop for treatment, police said.
Assistant Chief Constable Garry Shewan, from Greater Manchester Police, who is leading the policing operation, said: "There have been unwarranted attacks on police lines that have resulted in injuries. This is not a peaceful protest and we are facing a lot of hostility. We will take swift action when confronted with disorder.
"The number of arrests already made is a clear indication that this is not a peaceful protest and some demonstrators are determined to cause trouble.
"The actions of some demonstrators is resulting in injuries to others. This is not acceptable. I am determined to identify the offenders by whatever means and bring them to justice."
UK 
