West Ham have threatened to hand out lifetime bans to supporters found guilty of participating in abusive chanting heard during the club's Premier League match against Tottenham at White Hart Lane on Sunday.
Sections of the visiting crowd were heard singing anti-Semitic songs at Spurs, who have strong links to London's Jewish community. Reports also claimed that some of the Hammers fans hissed in reference to the murder of Jews in gas chambers during the Holocaust.
In addition, chants referencing the violence against Tottenham fans in Rome ahead of their Europa League tie against Lazio last week were also audible.
A West Ham club statement promises to "take the strongest possible action" against offending supporters and explains that the east London club will work with Tottenham to assist their investigation.
The statement reads: "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.
"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.
"During the 46 games in the Championship last season, West Ham United had zero arrests for racism or violence, so while we are surprised to see such reports today, we will examine any available evidence of such conduct thoroughly and take the appropriate action."