People who watched on as a demonstration broke out in a Sunderland community have been urged by police to come forward.
Four arrests where made at the protest in Hendon on Saturday afternoon.
Northumbria Police has not confirmed the reason for the event, which happened in the Toward Road and Peel Street area of the city.
One man was arrested on suspicion of assault and another for disorderly conduct, with a further two arrested for public order offences.
A force spokesman said more people than anticipated attended the demonstration and that officers "acted quickly to provide a proportionate response."
Inquiries are on-going and police are appealing for anyone who witnessed any criminal offences or disorder during the demonstration to get in contact.
Acting Detective Sergeant Paul Johnson, of Southern Area Command CID, said: "We believe there were witnesses who we have not yet spoken to and would ask these people to come forward and speak to us as they may have important information to help our inquiries."
Police can be contacted on 101 or Crimestoppers anonymously on 0800 555 111.