Atletico Madrid have condemned the racist abuse Real Madrid forward Vinicius Junior received prior to and during the Derbi Madrileno on Sunday.
The Brazil international was subjected to racist chanting and monkey noises from a large section of home fans both before the match outside the Wanda Metropolitano Stadium and inside the ground during the game.
La Liga have already confirmed an investigation is underway, while Atletico Madrid released a statement on Tuesday denouncing supporters who abused Vinicius.
"Atletico de Madrid roundly condemns the inadmissible chants that a minority of fans made outside the stadium before the derby was held. Racism is one of the biggest scourges in our society and unfortunately the world of football and clubs are not free from its presence.
"Our club has always been characterised by 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 athletes who support their team with passion and with respect for the rival," the statement read.
"These chants cause us enormous rejection and indignation and we will not allow any individual to hide behind our colours to utter racist or xenophobic insults. At Atlético de 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.
"For this we have contacted the authorities to offer them our maximum collaboration in the investigation of the events that occurred outside the stadium and demand the identification of the people who participated in order to proceed with the immediate expulsion of those who are members of the club.
"We also want to invite all professionals related to the world of football to make a deep reflection. Making clear once again our strongest condemnation of these events, which do not have the slightest justification, we believe that what has happened in the days leading up to the derby is inadmissible.
"Fans are asked for sanity and rationality and, however, professionals from different fields generated an artificial campaign during the week, lighting the fuse of controversy without measuring the impact of their actions and demonstrations.
"The pain that the red and white family feels for this event is enormous. We cannot allow someone to associate our fans with this type of behaviour and question our values because of a minority that does not represent us. Our decision is firm and resounding and we will not stop until we expel them from the red and white family because they cannot be part of it."
Vinicius was criticised by the Spanish media and Atletico Madrid players in the lead-up to the derby due to his celebratory dancing after scoring a goal, though certain comments - such as those from agent Pedro Bravo in which he suggested the winger "stop playing the monkey" - were judged to have had racist undertones.
Real Madrid ran out 2-1 winners on Sunday, with Rodrygo opening the scoring for Los Blancos and joining Vinicius in his trademark dancing.