UEFA are waiting for various reports from Liverpool's 4-1 Champions League win over Genk in Belgium last night, before deciding what action to take over a banner displayed by the away fans.
The Premier League club have condemned it, saying it showed a "racist stereotype" and was "completely unacceptable".
The banner showed a photo-shopped picture of Liverpool striker Divock Origi and it was taken down as soon as the club became aware of it.
A Liverpool spokesman said: "We sought to have it removed as soon as we became aware.
"The banner is highly offensive and inappropriate. We condemn its use and we will look to identify those responsible for bringing it into the stadium."