Tottenham Hotspur have issued a warning to fans about language ahead of the visit by West Ham to White Hart Lane in the League Cup.
The two London clubs face each other in the quarter final of the cup competition on Wednesday. The last time the local rivals met, West Ham beat Spurs 3-0 and set in train the course of events which led to manager Andre Villas-Boas being sacked from his post.
Warning fans about the language they use during the match echoes a campaign by the club to remove the word 'yid' from chants.
Two men were arrested on suspicion of inciting racial hatred on Twitter following the league meeting at White Hart Lane. Two men aged 22 and 24 were held by police over tweets which referenced Adolf Hitler and gas chambers.
In a statement on the official website, the club told fans: "The latter stages of any competition brings with it greater attention, particularly as this is a London derby, and so we once again call upon our fans to behave in a manner of which we can be proud.
"The club does not tolerate discrimination of any sort, on the pitch or in the stands, and both the police and ourselves shall take action against anyone heard using abusive, offensive or obscene language."