Barnsley have officially complained to police, who are to carry out their own inquiry into the incident, which occurred in the concourse of the north stand before the final whistle, with scenes of violence marring United's 2-0 fourth-round win.

A Barnsley spokesman said: "The club is going to launch a full investigation as soon as possible after substantial damage was caused in the concourse of the north stand.

"A complaint has been made to the police and we will be taking a look at CCTV footage of the incident before we can comment further."

Catering staff at Oakwell were forced to barricade themselves in a store room for fear of injury as United fans forced themselves behind the counter.

Barnsley failed to add a second successive Barclays Premier League scalp after ousting Burnley in the previous round as Sir Alex Ferguson's second string marched on into the last eight thanks to goals from Danny Welbeck and Michael Owen.