Chelsea condemned "abhorrent discriminatory behaviour" after reportedly preventing three supporters from attending their Europa League quarter-final first leg clash at Slavia Prague on Thursday.
The Premier League club's security team identified the fans from a video on Twitter showing them singing a derogatory song about former Chelsea forward Mohamed Salah, now of Liverpool, according to British media reports.
"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," Chelsea said in a statement.
"Such individuals are an embarrassment to the vast majority of Chelsea supporters who won't tolerate them in their club."