British soccer club Tottenham Hotspurs have described as "vile and unacceptable" a video appearing to portray West Ham United fans chanting an anti-Semitic song.
The footage was filmed by a passenger on the London Underground before West Ham's 2-2 draw with Spurs, who have historic links with the Jewish community, on Sunday.
Police said they are investigating the case and West Ham said it would enforce a "zero tolerance" police and ban any fans found to be involved.
The incident follows last week's racist abuse dished out by Chelsea fans to a black commuter on the Paris metro.
Sunday's video shows supporters of West Ham FC – which incidentally is Chelsea's main London rivals – standing in the Tube heading towards Tottenham's ground chanting "I've got foreskin, how about you? F******Jew."
Tottenham said they hope those involved are identified and dealt with seriously.
A Spurs spokesman 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 behavior are identified and dealt with in the strongest way possible."
Anti-discrimination group Kick It Out contacted police after the video footage surfaced on Twitter.
It said in a statement, it said: "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."
A British Transport Police spokesman said: "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 stressed they had a "zero tolerance" towards any type of discriminatory behavior.
The club said they had emailed every supporter who bought a ticket to Sunday'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 behavior 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 they will "continue to adopt a zero tolerance policy towards any form of discriminatory behavior and any fan found to be acting inappropriately – including racist, anti-Semitic and homophobic behavior – will be punished to the full extent of the law and banned from attending matches".
At the weekend, police released images of three men in connection with their investigation into Chelsea supporters who pushed a black man off a train and chanted a racist song in the French capital last Tuesday.
The incident happened ahead of Chelsea's Champions League clash with Paris St Germain, which ended 1-1.
Footage posted online showed the man being pushed back on to the platform amid chants of "we're racist, we're racist and that's the way we like it".