A child was hurt in a violent bust-up in the East Stand at Old Trafford between a small number of home and away supporters at a Europa League match between Manchester United and Liverpool.
The disorder led to the young child being caught in the crossfire and suffering minor injuries when hit by a plastic seat thrown by one of the offenders.
The incident happened prior to the final whistle of the last 16 second leg tie at the ground.
A number of other incidents also took place before and after the fixture on Thursday, March 17, said Greater Manchester Police.
Detective Sergeant Stephen Warriner said: "Football is a family event and the appalling violence that occurred that evening will not be tolerated by the clubs, the police or by the vast majority of supporters.
"A young child was hurt as a result of these mindless thugs, who paid absolutely no regard to the safety of those around them.
"A number of arrests have already been carried out, but now we need the public's help to ensure those people capable of carrying out such violence are no longer welcome at our football grounds.
"Please take a few minutes to view the images and if you recognise anyone please contact either myself or my team. If necessary this can be done anonymously."
Anyone with information should police on 0161 856 7525, or the independent charity Crimestoppers, anonymously, on 0800 555 111.
:: Two men have been charged with unfurling an "offensive banner" over a motorway bridge in Salford on the day of the match. They will appear in court later this month, police said.