Manchester United will review CCTV footage from its match against Southampton to identify supporters who ignored the club's request to stop performing an offensive chant about forward Romelu Lukaku.
The controversial chant was heard last week at Old Trafford in the Champions League and was quickly condemned by the anti-discrimination group Kick It Out.
United responded with comments from Lukaku, who thanked fans for their support but implored them to stop using the chant.
However, this morning in Southampton, a section of supporters was once more heard singing the same racist stereotype about Lukaku, a Belgian who is black.
"Manchester United has a zero tolerance stance on offensive chanting and behavior. The club and player have been clear in asking for an end to the chant," a club statement said. "The club has worked with relevant bodies and supporters groups in trying to eradicate any offensive behavior and will take further action against individuals if this continues.
"The club is in discussion with the police and has asked for CCTV footage from Southampton and will try to identify those who disrespected the player's wishes not to sing the song."
United manager Jose Mourinho said he doesn't understand the songs.