Is this the reason Manchester United and Liverpool fans clashed inside Old Trafford?

Manchester United and Liverpool supporters were involved in violent clashes inside Old Trafford during last night's Europa League clash.

Jurgen Klopp's side progressed to the quarter-finals after drawing 1-1 on the night (winning 3-1 on aggregate) - but the game was marred by fighting between the two sets of supporters.

Police and stewards were forced to step in after a group of Liverpool fans sneaked into the upper tier with the home supporters and unveiled a banner.

Liverpool Echo reporter James Pearce said: “Around half a dozen Liverpool fans sat in the United end unfurled an LFC banner and United fans around them reacted angrily.

“Punches were thrown before the police and stewards stepped in to restore calm.