Arsenal have launched an investigation into "two disturbing incidents" of anti-Semitism during their north London derby win against rivals Tottenham Hotspur on Sunday.
Meanwhile, anti-Semitic chants were also alleged to have been heard at a pub in Islington.
"Any kind of discriminatory abuse is not welcome at our club," Arsenal said.
The Premier League leaders added in a statement: "We have been made aware of two disturbing incidents over the weekend involving anti-Semitism which are now under investigation.
"There was an incident at the north London derby on Sunday involving Arsenal supporters in which one of our fans overheard grossly offensive anti-Semitic statements made by another Arsenal fan.