Arsenal have condemned racist abuse directed at Napoli defender Kalidou Koulibaly during Thursday night's Europa League match at the Emirates Stadium.
The Premier League club have launched an investigation to identify the individual after social media footage emerged of the incident, which if proven will see them handed a life ban.
Chelsea, meanwhile, denied entry to Thursday night's Europa League win at Slavia Prague for three individuals already identified as being involved in a social media video which included a racially abusive chant about Liverpool forward Mohamed Salah.
Anti-discrimination campaigners Kick It Out praised the swift action of Arsenal and Chelsea, whose security staff handed the trio over to police. The club will seek to ban the six supporters involved in the video.
Recent high-profile incidents, including monkey chants being aimed at England players during a Euro 2020 qualifier away to Montenegro, have again highlighted the problems within the game.
Brighton defender Bernardo has called for those found guilty of racial abuse in football to be sent to jail.
Arsenal have urged fans to continue to be vigilant and report any such incidents directly.
"We utterly condemn use of this type of racist language and have launched an investigation to identify the culprit," the club said in statement released to Press Association Sport.
"We operate a zero tolerance approach and anyone behaving like this is not welcome at Arsenal and will be banned from matches.
"We have an extremely diverse community of fans who are all part of the Arsenal family and such incidents are rare at Emirates Stadium.
"We encourage supporters to report any incidents as they happen to stewards or via our matchday alert service."
Brazilian Bernardo, who joined Brighton from RB Leipzig last summer, has called for the authorities to use the full force of the law against those responsible.
"I'm speechless because it's always the same thing, it doesn't seem like things are going to change and I don't see punishments – it's something that shouldn't be accepted anymore," Bernardo said, quoted on the Brighton website.
"I don't know how it works in England, but in Brazil racism is a crime and you go to jail if something like this happens. I think it should be the same over here – maybe things would start to change.
"When one incident happens, then a second and third one, and people notice that nothing is happening, they will carry on doing it.
"Unfortunately you can't change people's minds – if someone is racist, you can't change that, and I actually feel pity for that person.
"But what will stop people (being racist) is being punished. It's been too soft, it shouldn't be accepted and things should be more strict."
Manchester City and England forward Raheem Sterling has used his position to speak out against racism, as well as making defiant gestures on the pitch with goal celebrations and taking to social media.
