At around 5.05pm on Wednesday 16 December police were called to reports of a disturbance in Market Place, Stoke-on-Trent.
Multiple calls were received stating that a number of males were fighting in the street and throwing objects at one another.
Officers attended and found one man had been detained by an off-duty officer. The man, a 20-year-old from Stoke-on-Trent was arrested on suspicion of affray.
Two further Stoke-on-Trent men, both 21, were arrested on suspicion of public order and one for obstructing a police officer.
All three men remain in custody for questioning.
There were no reported injuries to anyone involved in the incident.
Inspector Rich Simpson, of Stoke-on-Trent North Local Policing Team, said: “We are aware that a short video clip of the aftermath of the incident is circulating on social media. This footage only shows the restraint of a suspect and not the violent circumstances prior to his detention. Officers will be speaking to all parties involved today and checking CCTV in the area.
“The off-duty officer took positive action to intervene the disorder and restrain a violent and aggressive suspect. He put himself in danger to protect other members of the public and used an appropriate restraint technique to detain the suspect while surrounded by a group of hostile men.
“Several members of the public came to the assistance of the off-duty officer and we’d like to thank them for their actions and community spirit.
“We will be carrying out a full investigation into the incident which was witnessed by numerous members of the public.
“Anyone with information about the incident please contact us on 101, quoting incident number 540 of December 16.”