"The incident has been reported to police and the club will be working with them to identify the individual responsible.
"We take a zero tolerance approach to this sort of behaviour, as and when the individual is identified, we will take the appropriate course of action."
Eight United players died when the plane carrying the squad home from a European Cup tie in Belgrade crashed on Feb. 6, 1958 after a refuelling stop at Munich.
Fifteen passengers and crew were also killed in the disaster.
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(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by Christian Radnedge)
