West Ham boss David Moyes said there is "no room for discrimination" and condemned footage of the club's fans apparently singing an anti-Semitic song towards a Jewish man on a plane.
A video emerged on social media on Thursday appearing to show some Hammers supporters on a flight to Belgium singing the offensive song as the man walks down the aisle to take his seat.
The fans on the flight were on their way to watch West Ham play Belgian side Genk in a Europa League tie.
The chant they can be heard singing is typically aimed at rivals Tottenham as an insult and reference to the Jewish ownership of the club.
Moyes, who marked his 1,000th game as a manager with a 2-2 draw at Genk to seal the Hammers' qualification from the group stage of the Europa League, joined his club in condemning the incident.
"Well I have to say first of all that I don't see our football club being like that. We are a diverse football club. There's no room for discrimination anywhere," said Moyes.
"I'm really disappointed to hear about it. I'm sure it's only individuals and not a big section of supporters. I'm just sorry to hear about it.
"I want this football club to be recognised for having a really good football team. I want this football club to be recognised as being a great club in London and well respected.
"We have incredible supporters who follow us home and away but I don't want any labels connected to this whatsoever - discrimination or racism, none at all. We don't want to be associated with supporters like this. I want us to fully move on from this."
The club condemned the video on Thursday night and vowed to punish any supporters identified with an indefinite ban.
A West Ham spokesperson said: "West Ham United is appalled by the contents of the video circulating on social media and condemn the behaviour of the individuals involved.
"The club is liaising with the airline and relevant authorities to identify the individuals.
"We continue to be unequivocal in our stance - we have a zero-tolerance approach to any form of discrimination. Any individuals identified will be issued with an indefinite ban from the club.
"Equality, diversity and inclusion are at the heart of the football club and we do not welcome any individuals who do not share those values."