West Ham pledged to impose life bans after some of its fans on Sunday were heard making chants about Adolf Hitler and also praising Italian club Lazio after an apparent anti-Semitic stabbing of a Tottenham fan on Wednesday in Rome ahead of a Europa League match against the Italian club.
West Ham fans were also heard hissing, a gesture widely seen as imitating the sound of the gas chambers used during the Holocaust. Tottenham is known to have a large Jewish fan base, which has long been subjected to anti-Semitic abuse at matches.
"I was very disappointed to hear some of the songs yesterday and it was embarrassing," Israel midfielder Yossi Benayoun, who is on loan at West Ham from Chelsea, wrote on Twitter.
The Metropolitan Police is looking into the chants heard during Sunday's globally-broadcast match at White Hart Lane after receiving a complaint from a member of the crowd.
Police had already arrested two fans at White Hart Lane for making Nazi-style salutes, described as a "racially aggravated public order offence." The fans accepted police cautions, which are given to people who admit to minor offences, but don't count as criminal convictions.
West Ham has identified one of the fans as an Upton Park season ticket holder and sent him a letter banning him from their ground, while the club said "other individuals identified can expect a similar swift and robust response."
The English Football Association is gathering video evidence from Tottenham and said it encourages clubs "to identify and ban for life any individuals involved in incidents of abusive chanting."
"There is no place for anti-Semitism or any form of discrimination in football," the FA said after launching a formal investigation.
West Ham, whose chairman David Gold is Jewish, said it is assisting Tottenham with the investigation "into the conduct of a small number of supporters and alleged inappropriate chanting."
"West Ham United will take the strongest possible action against any of their supporters, including enforcing life bans from the club, that are found guilty of behaviour which is categorically not condoned by West Ham United," the east London club said in a statement.
West Ham, which lost the game 3-1, stressed that no fans were arrested for "racism or violence" during 46 games while playing in the second tier last season before returning to the Premier League.
The main body representing British Jews nationally said chants glorifying Hitler were "a stain upon the character" of football.
"Clearly there is either a lack of understanding or a lack of compassion within some sections of the British football world about these issues — a lack of understanding or compassion which needs to be addressed," the Board of Deputies of British Jews said in a statement.
The Community Security Trust, which monitors anti-Semitism in Britain and offers security services, said it has received complaints from Jewish fans at the Tottenham match and is seeking an urgent meeting with the FA.
CST spokesman Mark Gardner said the abuse "risks seriously compromising" efforts to eradicate racism from football.
"Fans who indulge in racist or anti-Semitic behaviour should be arrested, charged and banned," he said. "We cannot have 'the football family' ignoring, and therefore encouraging, mass Nazi chanting."
Also Monday, another Premier League club, Norwich, complained to police after allegedly racist tweets were directed at defender Sebastien Bassong after Saturday's 1-1 draw at Everton.
English football is already taking moves to clamp down on racism after two-high profile cases.
Chelsea captain John Terry was banned for four matches and Liverpool striker Luis Suarez served an eight-match suspension after being found guilty of racially abusing opponents in games. Both players were kept on by their clubs.
Rob Harris can be reached at http://twitter.com/RobHarris