Chelsea have promised to take the strongest possible action and press for criminal convictions if anyone engages in anti-Semitic behaviour during Saturday's Premier League clash with Tottenham.
In a warning to both home and visiting supporters ahead of the Stamford Bridge fixture with Spurs, whose fans like to call themselves the 'Yid Army', the Blues vowed to come down hard on discriminatory behaviour.
A statement on chelseafc.com read: "The support of both sets of fans will make for an excellent atmosphere, and we urge everyone to keep that support positive.
"For a small minority this game also brings a deeply unpleasant and unwanted level of anti-Semitic abuse which has no place in football or anywhere in society.
"Opposition supporters using terms as a form of identity is no excuse for abusive chanting or behaviour. The club asks that all supporters realise such actions cause huge offence to those around them.
"The Football Association reiterated in its directive announced last year that the use of the 'Y' word in football stadiums is unacceptable and could amount to a criminal offence, leaving those fans liable to prosecution and potentially a lengthy Football Banning Order.
"This is fully supported by Chelsea Football Club. The diversity at Chelsea is obvious to everybody, and a source of pride.
"The players on the field, the supporters in the stands, our staff, directors and owner (Roman Abramovich, who is Jewish) all illustrate our vision as a club which embraces equality, regardless of race, gender, sexuality or religion.
"We have worked hard to combat all forms of discrimination at Stamford Bridge. If we receive evidence that supporters have engaged in anti-Semitic or any other form of discriminatory chanting or behaviour we will take the strongest possible action, including supporting criminal prosecution."