The FA is to make enquiries into an incident between Liverpool's Roberto Firmino and Everton's Mason Holgate in Friday night's FA Cup tie.
Referee Bobby Madley made reference to an allegation which had been reported to him.
The allegation is understood to be by the Toffees defender on the pitch and Everton officials after the match, and the governing body will now take a look at the flashpoint.
'The FA can confirm that referee Bobby Madley was made aware of an allegation during the Liverpool versus Everton game at Anfield last night and has subsequently reported this to The FA, which will now begin making enquiries into the matter,' said a statement from the FA.