Chelsea have promised to take the strongest possible action against any supporters found to have been involved in anti-Semitic chanting on Thursday night in Budapest, just days after four fans were suspended for abusing Raheem Sterling.

Chelsea and the Metropolitan Police opened investigations after alleged racist abuse was directed at Manchester City’s Sterling by a section of home supporters during last Saturday’s match at Stamford Bridge.

Minutes into the Blues’ next game – Thursday night’s Europa League clash with Vidi in Budapest’s Groupama Arena, which was drawn 2-2 – a vocal minority of Chelsea supporters were heard singing a derogatory chant about Tottenham supporters, featuring anti-Semitic language.

Chelsea launched a campaign in January to raise awareness and educate about anti-Semitism in football and the club, including owner Roman Abramovich, who is Jewish, is disgusted at the latest incident.

Chelsea have promised firm action
Chelsea have promised firm action (Steven Paston/PA)

A Chelsea spokesman said: “Anti-Semitism and any other kind of race-related or religious hatred is abhorrent to this club and the overwhelming majority of our fans. It has no place at Chelsea or in any of our communities.

“We have stated this loud and clear on many occasions from the owner, the board, coaches and players.

“Any individuals that can’t summon the brainpower to comprehend this simple message and are found to have shamed the club by using anti-Semitic or racist words or actions will face the strongest possible action from the club.”

The Sterling incident overshadowed Chelsea’s 2-0 Premier League win over last season’s champions City and the latest incident is sure to be investigated by UEFA, who said it is awaiting the referee’s report.

Chelsea’s next league game is at Brighton on Sunday, with Alvaro Morata a doubt due to his first-half substitution with a knee injury.

Olivier Giroud, Morata’s replacement, scored a free-kick to earn a draw and spare the Blues an embarrassing defeat.

Maurizio Sarri has concerns about Alvaro Morata
Maurizio Sarri has concerns about Alvaro Morata (John Walton/PA)

Willian’s free-kick had earlier been cancelled out by an Ethan Ampadu own goal, before Vidi took the lead through Loic Nego’s sumptuous volley.

On Morata, Sarri said: “The first impression of the doctor (is) maybe it is not a serious injury.  But, of course, with this situation we have to wait.”

Morata and Giroud have shared the striking responsibilities this season, although Eden Hazard was deployed as a ‘false nine’ in last Saturday’s defeat of Manchester City.

The Blues have five remaining matches in December and should Morata be ruled out for any length of time, it would place additional strain on Giroud.