Tottenham Hotspur and Crystal Palace are working with the Metropolitan Police to investigate an allegation of racial abuse towards Son Heung-min, both clubs said on Sunday.
Videos on social media appeared to show a fan at the Tottenham Hotspur Stadium making a racist gesture towards the South Korean forward as he walked past Palace fans after being substituted in a 1-0 win over the visitors on Saturday.
"We are aware of a video circulating online (as well as reports made directly to us) regarding an individual in the away end at Spurs yesterday, appearing to make racist gestures towards Heung-Min Son," Palace said in a statement.
"Evidence has been shared with the police, and when he is identified, he will face a club ban. We will not tolerate such behaviour in our club."
Son has been subjected to racist abuse in the past. Last year, Chelsea indefinitely banned a season ticket holder following reports that Son was racially abused during a Premier League game at Stamford Bridge.
"We will do everything in our powers to ensure that if found guilty, the individual will receive the strongest possible action - as was the case earlier this season when Son suffered similar racial abuse at Chelsea," Spurs said.