Millwall Football Club said it was "appalled" by footage which appears to show supporters racially abusing a Leeds player during a match earlier this season.
It has urged Sky Sports News - which aired the scenes on Monday night - to pass the clips to police and has promised to ban any individuals for life if they are found guilty.
The footage appears to show fans hurling insults at Leeds forward and Senegal international El-Hadji Diouf during a clash between the two clubs on November 18.
Millwall has vowed to reopen an investigation into allegations of racial abuse which initially emerged online.
Lions chief executive Andy Ambler said: "Like all Millwall fans and football fans generally, we're appalled by the footage we've seen."
He added: "Clearly that behaviour is unacceptable in any football ground in the country and at Millwall we will ban the individuals for life and we hope that Sky will pass the footage to the police so that further action can be taken.
"Sadly racism exists in our society and certain individuals want to bring it into football grounds. It's down to us in football do to more. We think football is the solution to the problem and the work that we do will continue and we need to continue it.
"That day against Leeds obviously there was an allegation of abuse made online initially. We investigated it straight away. We interviewed stewards, police, players, we looked at the TV footage too as it was live on Sky.
"After speaking to the player who had the alleged abuse at him during the day, he said that he heard no abuse on the day so that was basically at that point the end of the investigation - although we're going to open it again now."
David Bernstein, the FA chairman, is treating allegations with the utmost importance, telling Sky Sports News: "These issues bother me intensely. They have become top of my agenda in terms of moving these things on and combating these things. The awareness of it could not be higher."