Manchester United have announced they have asked for CCTV footage from today's game at Southampton.
They want to try to identify those who chanted a song about striker Romelu Lukaku during the Premier League match, with a view to taking further action.
The 24-year-old striker continued his fine start to life at United at St Mary's this afternoon, when his first-half effort was enough to secure a hard-fought win.
Lukaku has quickly become a fans' favourite, although a song to the tune of the Stone Roses' 'Made of Stone' has caused controversy as it references the size of his penis - a song anti-discrimination body Kick It Out have called "offensive and discriminatory".
Both club and player urged fans to refrain from chanting the song, but it could be heard in Southampton after he scored in the 20th minute, as were chants of "we'll sing what we want".
A United spokesperson said afterwards: "Manchester United has a zero tolerance stance on offensive chanting and behaviour.
"The club and player have been clear in asking for an end to the chant.
"The club has worked with relevant bodies and supporters groups in trying to eradicate any offensive behaviour 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."