Atletico Madrid have condemned the racist abuse directed at Real Madrid forward Vinicius Junior by supporters, promising the "immediate expulsion" of any members who were involved.
Sunday's LaLiga derby between the two capital clubs was marred by pre-match scenes of Atletico fans singing racist chants about the Brazilian forward.
The chants came less than a week after football agent Pedro Bravo urged the Real Madrid winger to "stop playing the monkey" in relation to the forward's customary dancing celebration. Bravo later apologised, insisting he did not mean to cause offence with the comments made on TV show El Chiringuito.
Vinicius vowed to continue celebrating in such a way and was met with a wave of support, including from compatriots Neymar, Pele and Gabriel Jesus, but he was still targeted by some Atletico fans ahead of Sunday's match.
Atletico have belatedly spoken out against the abuse suffered by the forward and offered their cooperation to the police.
"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," the statement read.
"These chants provoke enormous repulsion and indignation. We will not allow any individual to hide behind our colours to utter insults of a racist or xenophobic nature. At Atletico Madrid, 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.
"To this end, we have contacted the authorities to offer them our full cooperation in the investigation of the events that took place outside the stadium. We ask them to identify the people who participated [and] to proceed with the immediate expulsion of those who are members of the club.
"We would also like to invite all professionals involved in the world of football to reflect deeply. Making clear once again our strongest condemnation of these events, which have no justification whatsoever, we believe that what has happened in the days leading up to the derby is unacceptable.
"Fans are asked for sanity and rationality, and during the week, professionals from different fields generated an artificial campaign, lighting the fuse of controversy without measuring the repercussions of their actions and manifestations.
"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.
"Our decision is firm and emphatic. We will not stop until we expel those involved from the red and white family because they cannot be part of it."