Thirteen men have been arrested during two protests in Leicester, which sparked the biggest police operation in the county for 25 years.
The English Defence League (EDL) held a static demonstration and Unite Against Fascism (UAF) staged a counter-protest on Humberstone Gate East.
Riot police moved in after several fireworks, bottles and coins were thrown.
There were also reports of violence away from the demonstration site.
Gangs were seen throwing stones and bricks at two coaches carrying EDL supporters as they left the city.
Those arrested at the main protest site were aged between 30 and 42 and were not from the Leicester area.
One has been arrested on drugs offences, two for possession of an offensive weapon and two for minor public order offences.
About 2,000 EDL protesters gathered in the city - about 1,000 gathered at Humberstone Gate and 600 UAF protesters also went to the site.
A policeman was taken to hospital with a leg injury and two protesters were treated by paramedics for minor injuries.
Nick Cimini, an anti-fascist protester and a shop worker from Derby, said: "We've got to show them that racism and fascism are not welcome here.
"If you turn a blind eye, they will come and smack you in the face, particularly ethnic minorities, homosexuals and anyone who does not fit their narrow definition of English."
EDL member Lucy Bethell, 23 and from Manchester, said: "I've come to this great city of Leicester to protest against Islamic extremism.
"I am not a racist. I have Muslim and black friends. There is a big difference between racism and protesting against Islamic extremism.
"I joined the EDL because it made no sense that people defending Englishness were labelled as troublemakers."
Officers from 13 forces were on hand to maintain order in the city.
Metal barriers were put up on Humberstone Gate and the windows of several shops were covered with boards.
Sheila Lock, chief executive of the city council, said: "I've been overwhelmed by the reaction of both the public sector and the community.
"Both community leaders and faith leaders have said they will stand for the importance of unity and respect and I believe Leicester will be stronger for this because that's what people have said to me."
A series of "green-themed peace events" are being held on Humberstone Gate as part of the event on Sunday from 1300 to 1600 BST.