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 today.
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 have 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" have broken 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."
Riot police and mounted officers armed with batons are trying to keep the crowds in check in front of the town hall.
Police dogs have been deployed in a bid to control the crowds and a police helicopter has also been dispatched.
It is unclear how many of those arrested are EDL and how many are UAF.
Weyman Bennett, the UAF joint secretary who organised the protest, was arrested on suspicion of conspiracy to commit violent disorder, police said.
Two UAF demonstrators have been taken to hospital, one with a minor head injury and the other with a minor ear injury, police said.
A 19-year-old man has received treatment for an ongoing health problem, another man has fractured a finger.
A 16-year-old girl has been treated after suffering panic attack, police said.
Most shops and pubs are closed in the area, and most taxi firms have pulled their drivers off the roads.
Second World War veteran Bertie Lois, 89, who lives in Farnworth, Bolton, is protesting with the UAF.
He said: "I fought the Second World War against these Nazis. What did I fight for if we let them? The EDL are the enemy. I would say to them 'you are the guys we fought for, what are you doing?'
"I am also here because I am against the war in Afghanistan."
The EDL describes itself as a peaceful, non-political group campaigning against "militant Islam".
But ugly scenes also marked one of their protests in Manchester last year, with 44 arrests and 10 injuries.Reuse content