Thursday 24 November 2016 12:29, UK
La Liga has written to the Spanish FA (RFEF) to ask it to investigate chanting aimed at Real Madrid and Cristiano Ronaldo during their game with rivals Atletico on Saturday.
Six incidents have been deemed "racist or worthy of inciting violence" by La Liga.
According to official match observers, sections of Atletico fans were heard chanting "Madristas, son of b***hes" and "That Portguese, what a son of a "b***h he is" on various occasions.
RFEF will now start an investigation and speak to both clubs before deciding whether any punishments are necessary.
Atletico star Koke was also accused of a homophobic attack on Ronaldo after an altercation during the game but this alleged incident does not appear to have been mentioned in the letter.
Ronaldo scored a hat-trick as Real thrashed Atletico 3-0 in the final ever Madrid derby at the Vicente Calderon.
The win took Zinedine Zidane's side four point clear of Barcelona at the top of the La Liga table.
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