Sheffield United say troublemakers involved in a huge brawl after yesterday's game could be banned.
More than 200 supporters of both teams were reportedly involved in ugly clashes after the Blades' 1-0 defeat to Middlesbrough at the Riverside Stadium yesterday.
Police said children as young as 10 were injured in the violence, with reports of rocks and bottles being thrown, and a wounded police officer was taken to hospital.
Sheffield United's chief operating officer Andrew Birks said: "First and foremost our best wishes go to the police officer and his family for a quick recovery.
“We will not condone this type of behaviour, particularly when the vast majority of our thousands of fans attend home and away fixtures simply to enjoy watching the Blades in action.
"We are assisting Cleveland Police and others to identify the troublemakers and bring them to justice, which may include the potential use of banning orders."
Cleveland Police said the violence began after United fans invaded the pitch to celebrate a late goal which was subsequently disallowed, and fighting continued outside the ground in the car park.
It said five people had been arrested on suspicion of a number of offences, with more arrests expected as the investigation unfolds.
Assistant Chief Constable Jason Harwin said the force would work closely with the two Championship clubs to identify the offenders and bring them to justice.
A report on a Sheffield United supporters blog questions the police handling of the incident, claiming Blades fans were held outside the ground for 'no reason' and officers had been heavy-handed with some fans.
The author claims bottles and other objects were thrown by Middlesbrough fans, before being launched back by United supporters, and says there was a 'scuffle' in the car park which lasted no more than 15 seconds until it was broken up by officers.
Anyone with information is asked to call Cleveland Police on the non-emergency number 101.