Leeds United say an arrest has been made and an investigation is under way after an alleged incident of racism from the crowd during their 4-1 home defeat by Arsenal.
Gunners substitute Rob Holding approached the fourth official in the 33rd minute, saying he had heard racial abuse from a Leeds supporter.
"Racism will not be tolerated at Leeds United and any supporter found to be using racist language will be subject to a life time ban for all Leeds United games," said a club statement.
Arsenal boss Mikel Arteta said: "It is very disappointing because we have done so much in football to try to avoid that.