Police have confirmed they are investigating a complaint following footage of anti-Semitic chanting at Upton Park appearing on the internet.
West Ham have also promised to look into the claims that some of their fans engaged in the racist chanting on the day of the 4-3 home defeat by Tottenham.
The Hammers were beaten by their London rivals on Sunday and the footage appeared on the internet the following day but has now been removed.
A police spokesperson said: 'We can confirm that officers from the Public Order Branch Football Unit are investigating a complaint of an anti-Semitic video being shown on an internet site.
'The film appears to be made at the West Ham v Tottenham match on March 4, we have contacted the internet site to request a removal of the film.'
The club said in a statement: 'We are a leading campaigner in the Kick Racism out of Football campaign and we will not tolerate racist behaviour. We will investigate this matter fully.'