Youths dragged a Union flag from a man's hands
A police review of an anti-islamic rally and counter protest in Birmingham city centre in which 35 people were arrested is being carried out.
West Midlands Police said a "post operation investigation" was under way.
Police said Saturday's rally was made up of football fans calling themselves the English and Welsh Defence League and Casuals United.
The counter-protest was organised by campaign group Unite Against Fascism, West Midlands Police said.
Police described the trouble as "sporadic incidents of disturbance in the city centre" with the majority of the arrests being for disorder.
Three people were hurt on Saturday but numbers may rise, say police.
West Midlands Police said it also expected the number of arrests to increase as photographs and video images are studied.
Anyone found to be engaged in acts of criminality will be prosecuted, a spokesman said.
There was one report of criminal damage to a vehicle, but more were expected. No police officers were hurt.
Resident Gary Nichols witnessed the disturbances from his city centre flat and said he was unable to go outside for about two and a half hours.
Ch Insp Mark Payne said the force was looking at applying for injunctions to prevent people travelling to the West Midlands who are intent on causing trouble.
"The events of yesterday are a very rare occurrence and normal city centre life resumed within a short space of time," he said.
"I want to reassure all members of the community that the city centre is, and will continue to be a safe place to live, shop and visit.
He said the force has no powers to ban or stop peaceful protests and would not seek to do so, but if "criminal acts or racially aggravated incidents are reported, then police will arrest and prosecute anyone found to be responsible".