A group of Real Madrid fans has been reported to the Spanish Football Federation for racist chanting during their side's league match at Levante during the weekend.
Referee David Fernandez Borbalan noted the behaviour of visiting fans in his report on the match which Real won 2-0.
"During the second half a group of Real Madrid fans ... shouted monkey noises whenever Levante's two coloured players wearing the numbers seven and 16 touched the ball," said Fernandez Borbalan.
Colombian forward Edwin Congo and Ivory Coast midfielder Felix Ettien were the two players targeted by the supporters who appeared to belong to the club's radical Ultra Sur group of fans.
"I don't understand it, it's very upsetting when this sort of thing happens," said former Real Madrid player Congo.
Racist behaviour by fans has been on the rise in Spanish football this season, with insults directed at visiting black players a common occurrence at many grounds.
Espanyol's Cameroon goalkeeper Carlos Kameni had a banana thrown at him by an Atletico Madrid fan during his side's league match at the Calderon on Saturday.