A 17-year-old man was arrested at Wembley prior to Tuesday night's Carabao Cup semi-final first leg between Tottenham and Chelsea for "a racially aggravated public order offence", the Metropolitan Police said.

Press Association Sport understands the alleged offence was anti-Semitic. The arrest was made at around 7.40pm, 20 minutes prior to kick-off.

A statement from the Met Police's Football Unit on Twitter read: "Police have arrested a 17 year old male for a racially aggravated public order offence at tonight's @SpursOfficial v @ChelseaFC

"The male is currently being dealt with at a North London police station."

Tottenham and Chelsea cautioned supporters to behave prior to the match, after recent incidents of discriminatory behaviour.

Last January Chelsea launched the 'Say No to Anti-Semitism' campaign and in 2010 joined with anti-discrimination group Kick It Out to "try and rid the game of the Y-word".

However, the waters are muddied by the fact Tottenham supporters use the Y-word in large numbers at matches.

Last week the World Jewish Congress and the Board of Deputies of British Jews urged Spurs to take a stand against its use. Yet the club maintain the term is not meant to cause offence.

Chelsea supporters' groups took to social media to issue reminders to fans to be on their best behaviour, using the hashtag ChelseaTogether.

A chant of 'Yids' was heard in the second minute, but it appeared muted, with more Spurs fans opting to join in further singing of a song incorporating the word in the West Stand after 16 minutes.

Blues fans have been under the spotlight in recent weeks after a number of high-profile incidents, including a derogatory chant about Spurs supporters that featured alleged anti-Semitic language at a Europa League match in Hungary last month.

And a Spurs fan was banned and fined for throwing a banana skin at Arsenal's Pierre-Emerick Aubameyang during the north London derby late last year.