Three Chelsea fans have been turned away from a Europa League quarter-final after they allegedly sang a racist song about Mohamed Salah.
The fans were identified by Chelsea Football Club as appearing in a video which has been widely shared on social media.
The video appears to show them singing a racist song about the Liverpool forward.
In a statement, the club said: “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.”
The three fans were refused entry to Thursday’s game in Prague.
Liverpool also released a statement, which said: “The video circulating online, showing vile discriminatory chants being aimed at one of our players, is dangerous and disturbing.
“Already this season, we have seen repulsive discriminatory abuse inside stadiums in England, Europe and across the world; abuse that was captured on devices and put into the public domain. We have also witnessed numerous hateful attacks on social media.
“This behaviour needs to be called out for what it is – unadulterated bigotry.”
A Merseyside Police spokesman said: “[We are] currently investigating the publication of a number of offensive tweets made in relation to a Liverpool footballer.
“The language used in the tweets is abhorrent and we are taking the reports extremely seriously. Detectives from Merseyside Police are linking in with the Metropolitan Police Service in relation to the latest tweet.
“We will continue to work with Liverpool Football Club to ensure that those who use the Internet to target others, and who commit criminal offences such as harassment or hate crime in doing so, understand that they are not beyond the law.”