The Football Association (FA) announced on Monday that they have launched an investigation into reports of anti-Semitic abuse by West Ham United fans towards supporters of Tottenham Hotspur.
Some West Ham fans were reported to have mocked the gassing of Jews in the Holocaust and chanted about Nazi dictator Adolf Hitler during Sunday's game between the clubs, in reference to Spurs' links to the Jewish community.
"The FA can confirm it has begun investigating reports of abusive chanting at the Tottenham versus West Ham United fixture," said an FA statement.
"The FA governance department has this morning (Monday) contacted both clubs and will continue to make enquiries into the matter in the coming days."
Scotland Yard revealed that two West Ham supporters had accepted police cautions after being arrested during the game.
A spokesman for London's Metropolitan Police said: "Two men were arrested during the football match between Tottenham Hotspur and West Ham on Sunday November 25 on suspicion of a racially aggravated public order offence.
"The men accepted a police caution."
The incidents came just days after a Tottenham fan was stabbed before a Europa League game against Lazio in Rome in an apparently anti-Semitic attack by Italian hooligans.
West Ham supporters also sang "Viva Lazio", "Can we stab you every week?" and hissed on several occasions, apparently mimicking the noise of the gas chambers used in the mass execution of Jews during World War II.
The east London club had earlier pledged to support any FA investigation and said they would hand out life bans to any fans found found guilty of anti-Semitic chants.
"West Ham United are in contact with Tottenham Hotspur to assist them with their investigation into the conduct of a small number of supporters and alleged inappropriate chanting during yesterday's match at White Hart Lane," the club said.
"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."
In response, the FA said: "We note the statement issued by West Ham and encourage clubs to identify and ban for life any individuals involved in incidents of abusive chanting."
Tottenham are preparing a report to be sent to the FA and a club spokesman confirmed on Monday that their evidence would contain "relevant CCTV footage".
Before the news of the two police cautions emerged, Peter Herbert, chairman of the Society of Black Lawyers, confirmed that his organisation had contacted police to complain about the West Ham supporters' actions.
Asked if he would take the issue to the police, Herbert told Sky Sports News: "We've done so already.
"In fact, we were due to meet a borough commander of the Met Police either later this week or early next week, and it's one of the things that will be on our agenda.
"As far as we're concerned, there has to be zero tolerance of this. If these people can be identified on camera and prosecuted, then that is something we'd like to see happen."
The Community Security Trust (CST), an anti-Semitism monitoring charity, said it had received complaints from members of the Jewish community, including people who attended the game.
"The days of English football crowds making massed monkey noises are thankfully gone, but massed anti-Semitic chanting about Hitler and gassing was clearly heard yesterday (Sunday) from a loud section of West Ham fans," said CST spokesman Mark Garder.
"We have heard such abuse against Spurs before and it risks seriously compromising the work against racism at all levels of the game."
The anti-racism group Kick It Out said it was looking into the reports of abuse as well.
Kick It Out chair Lord Herman Ouseley said: "Kick It Out is following up with both clubs after the reports circulated concerning unacceptable chanting at White Hart Lane and is awaiting reports with further detail."
Tottenham won the game 3-1.