The Blues, already qualified for the Europa League knockout round, closed out their group stage with a 2-2 draw in Hungary on Thursday, with Olivier Giroud snatching a point on a 75th minute equaliser.
However, the result has been marred by reports of anti-Semitic chants being sung by a section of supporters during the first few minutes of the match.
A Chelsea spokesperson says the club stands against such hate speech, promising “the strongest possible action” if any fans are discovered to have participated in these acts.
“Anti-Semitism and any other kind of race-related or religious hatred is abhorrent to this club and the overwhelming majority of our fans,” the spokesperson said. “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 allegations in Hungary come just days after an investigation was launched by Chelsea, the Football Association and Metropolitan Police into allegations of racist abuse toward Manchester City star Raheem Sterling last weekend.
The club have since suspended four fans over the alleged incident, pending further investigation from the Blues.
Sarri condemned the alleged actions of those fans in the 2-0 victory over Man City prior to the match against Vidi, saying he thought it was “disgusting.”
Chelsea have previously called for an end to an anti-Semitic chant in 2017, while two Blues fans were given suspended prison sentences in 2015 for shoving a black man away from the doors of the Paris Metro as he tried to board.