Referee Juan Martinez Munuera stopped the match in the 36th minute as part of LaLiga's protocol against racism after he heard racist abuse directed at the 21-year-old Spain international, who was born in Pamplona to Ghanaian parents.

Atletico, who did not immediately respond when contacted by Reuters for comment, have also been fined 20,000 euros ($21,360). They have 10 days to appeal.

The RFEF said in a statement on Tuesday that the closed area in the stands must display a visible message condemning violent, racist, xenophobic and intolerant acts in football and supporting fair play.

A few minutes after he was abused, Williams scored and ran in front of the south stand tapping his arm in reference to his skin colour.

After the match, which Atletico won 3-1, he told DAZN: "There are stupid people everywhere but nothing happens, we have to keep fighting so this changes little by little."

The incident was the latest in a series of episodes that have fuelled the debate around racism in Spanish football. There have been 16 incidents of racist abuse against Real Madrid's Brazil winger Vinicius Jr reported to Spanish prosecutors by LaLiga in the last two seasons.

Earlier this month, Spanish TV station Movistar Plus+ fired analyst German Burgos after Barcelona and Paris St Germain refused to give interviews to the network following a comment which was interpreted as racist about Barcelona's Lamine Yamal.

Also in April, Getafe were ordered to partially close their central stand for three matches following racist and xenophobic abuse suffered by Sevilla manager Quique Sanchez Flores and player Marcos Acuna in a LaLiga game.

The same day, a Spanish third-division match between Rayo Majadahonda and Sestao River was suspended after Rayo's Senegalese goalkeeper Cheikh Kane Sarr confronted a rival fan who he said was racially abusing him.