West Ham say they will ban for life anyone found guilty of homophobic abuse after two fans were arrested during Saturday's match against Brighton.
The Metropolitan Police said there were three arrests in total at the London Stadium, two for homophobic incidents and one for assault on an away supporter.
A Hammers spokesperson said: "West Ham United is disgusted to hear of alleged homophobic incidents at the game against Brighton & Hove Albion.
"The matter is now with the police but anyone found guilty of acting in a discriminatory manner will be banned for life from London Stadium and from travelling with the club.
"The club is unequivocal in its stance – we have a zero-tolerance approach to any form of discrimination.
"Equality and diversity is at the heart of the football club and we are committed to continue ensuring that everyone who enters London Stadium is free to enjoy watching their team play football in an inclusive environment."