Atletico Madrid have condemned “unacceptable” chants by a “minority” of fans towards Real Madrid’s Vinicius Junior outside their stadium before Sunday’s La Liga derby.
Some fans sang racist songs when entering Wanda Metropolitano before Real’s 2-1 win.
Atletico say they will co-operate in an investigation by the authorities.
“These chants provoke enormous repulsion and indignation,” an Atletico Madrid statement read.
“We will not allow any individual to hide behind our colours to utter insults of a racist or xenophobic nature.”
On Monday, La Liga condemned “hate speech” and said it will work with authorities “to identify and bring to justice” the culprits.
Sunday’s abuse followed on from comments by some pundits in Spain recently criticising Vinicius’ goal celebration, in which he dances by corner flag.
The 22-year-old Brazil forward responded on Friday, saying “the happiness of a black Brazilian in Europe” was behind recent criticism.
Atletico Madrid have asked the authorities to identify the fans who participated in the chanting so they could proceed with their “immediate expulsion” from the club.
The statement added: “Our club has always been known for being an open and inclusive space for fans of different nationalities, cultures, races, and social classes, and a few cannot tarnish the image of thousands and thousands of Atleti fans who support their team with passion and respect for their opponents.
“We have zero tolerance for racism, our commitment to the fight against this social scourge is total, and we will not stop until we eliminate it.
“The pain felt by the red and white family for this event is enormous. We cannot allow anyone to link our fans with this behaviour and question our values because of a minority that does not represent us.”
Agent Pedro Bravo said during a Spanish television discussion on Vinicius that “in Spain, you have to respect rivals and stop playing the monkey”, leading to accusations of racism. He has since apologised.
Brazil international Vinicius, who has scored five goals in eight games for the European champions so far this season, listed other stars who danced in their celebrations in a statement on Friday.
Vinicius was supported by several Brazilian football stars on social media, including Pele and Neymar, while Real Madrid also released a statement condemning the pundit’s comments on Friday.