Uefa has opened disciplinary proceedings against Manchester United and Liverpool after crowd trouble marred the second leg of their Europa League last-16 clash.

Supporters were involved in unsavoury scenes in the East Stand at Old Trafford towards the end of Thursday’s 1-1 draw, which saw Liverpool progress 3-1 on aggregate.

Greater Manchester Police arrested five men – four Liverpool fans and one United supporter – after fights broke out and flares and smoke bombs were lit in the stands.

Uefa confirmed on Friday that proceedings had been opened against United on charges of blocked stairways, crowd disturbances and objects being thrown.

Liverpool, meanwhile, were charged with setting off fireworks, throwing objects, crowd disturbances and for delaying the kick-off.

The visitors face a further charge of “illicit chants”, with some supporters alleged to have taken part in songs referencing the Munich air disaster in 1958, in which 23 people – including United players and staff – were killed.

United escaped punishment from Uefa after some fans were heard singing offensive chants relating to the Hillsborough disaster during the first leg at Anfield.

“The case will be dealt with by the Uef Control, Ethics and Disciplinary Body on May 19,” Uefa’s statement added.