UEFA has announced that it is investigating reports of "illicit chanting" during the Europa League tie between Liverpool and Manchester United.
The two most successful clubs in English football met on the European stage for the first time ever in the last 16 of the competition, but the tie was soured by disturbances off the pitch.
Both sets of fans have been accused of the illicit chanting over the two legs, and the clubs must now provide a statement for the governing body of European football.
"UEFA has recently been made aware of several reports concerning alleged illicit chanting on the occasion of the UEFA Europa League ties between Liverpool FC and Manchester United FC of 10 and 17 March 2016," read a statement.
"As a result, a UEFA ethics and disciplinary inspector decided to investigate further and gather potential evidence. The two clubs have thus been asked to provide statements relating to the alleged incidents within 10 days."
Liverpool won the tie with a 3-1 aggregate victory to set up a quarter-final clash against Borussia Dortmund.
