A man was left with a fractured jaw, cuts and bruises after he was attacked by at least 10 men as he walked along a Sheffield street.
Police said a car stopped behind the man as he walked along Staniforth Road, Darnall, and a number of men got out and were joined by another group of around 10.
The yobs then repeatedly punched and kicked the 29-year-old, leaving him with a fractured jaw, cuts and bruises.
A South Yorkshire Police spokeswoman said the attack was for ‘unknown reasons’.
An investigation into the incident at 12.40am on Saturday is now underway.
Witnesses to the assault or anyone with information should call South Yorkshire Police detectives on 101 or Crimestoppers, anonymously, on 0800 555111.