The supporters sang the Islamophobic song against the Liverpool forward in Prague on a video which has spread across social media.
The fans can be heard singing, “Salah is a bomber,” leaving fans outraged.
Salah previously played for the Blues in 2014 but left for Fiorentina on loan next season before a permanent move to Roma in 2016.
Chelsea have released a club statement, labelling those fans involved in the chants as "embarrassing."
"Chelsea FC finds all forms of discriminatory behaviour abhorrent and where there is clear evidence of Chelsea season ticket holders or members involved in such behaviour, we will take the strongest possible action against them.
"Such individuals are an embarrassment to the vast majority of Chelsea supporters who won't tolerate them in their club."
Chelsea were investigated earlier this year after alleged racist incidents during their Europa League away trip to Budapest to play Mol Vidi.
The investigation centred around antisemetic chanting against Tottenham fans, but was eventually dropped by Uefa.
The Blues face Slavia in the first leg of their quarter-final before travelling to Anfield to take on Salah’s Reds this weekend.
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