23 February 2015, 19:12
Police are investigating video appearing to show West Ham fans signing anti-Semitic songs at Tottenham supporters on a train.
The video, filmed by a passenger on the London Overground, comes five days after an incident involving Chelsea football fans on a Paris Metro train.
The short clip shows a group of fans standing in the Tube chanting "I've got foreskin, how about you?"
The latest incident happened before a match between West Ham and Tottenham, which has historic links to the Jewish community, at White Hart Lane yesterday. The game ended 2-2.
The footage was uploaded to Twitter by Spurs fan @RomanGeezer, who said: "On the train on the way to the game, West Ham fans break into song in Stamford Hill, a Jewish area, scum."
There were also allegations that West Ham fans made anti-Jewish comments on social media.
Anti-racism organisation Kick It Out said in a statement: "Kick It Out has received several reports via social media about the footage and will be liaising with British Transport Police on the matter.
"In addition, we have been informed of a number of anti-Semitic tweets which we are reporting to the police."
Tottenham said it hopes those involved are identified and dealt with seriously.
A spokesman for the club said: "Anti-Semitism in any form is wholly unacceptable and we support all efforts to kick it out of the game.
"We hope that those individuals responsible for this vile behaviour are identified and dealt with in the strongest way possible."
At the weekend, Scotland Yard released images of three men in connection with their investigation into a group of supporters who allegedly pushed a black man off a train and chanted a racist song in the French capital on Tuesday.
The incident happened ahead of Chelsea's Champions League clash with Paris Saint-Germain, which ended 1-1.
Footage posted online showed the commuter - named in reports as Souleymane S - being pushed back on to the platform amid chants of ''we're racist, we're racist and that's the way we like it''.
British Transport Police is investigating the latest incident and said it takes allegations of racism "very seriously".
A spokesman said: "We are encouraged the public has the confidence to report incidents of inappropriate and offensive football-related behaviour to us.
"Officers ask anyone who has information or footage on this latest incident on the London Underground at Stamford Hill, or any others, to contact us so the matter can be fully investigated by detectives.
"We take these incidents very seriously, and it is clear what happened on the Paris Metro and at St Pancras the following night were not isolated events."
West Ham said it had emailed every supporter who bought a ticket to yesterday's game to remind them they were acting as ambassadors for the club.
A spokesman said: "If any individual is found to have behaved in an inappropriate way, the club's simple, zero-tolerance policy dictates that they will face the strongest possible action, including the option of a life ban from the Boleyn Ground.
"If anyone has any information on such behaviour we would urge them to report it to the club, Kick It Out or the police so it can be investigated thoroughly."
In the letter to fans West Ham wrote that it will "continue to adopt a zero tolerance policy towards any form of discriminatory behaviour and any fan found to be acting inappropriately - including racist, anti-Semitic and homophobic behaviour - will be punished to the full extent of the law and banned from attending matches".