The Premier League has said dealing with "tragedy chanting" has become a "matter of urgency" after Leeds United's clash with Manchester United at Elland Road was marred by rival supporters taunting each other with songs about tragic loss of life involving the two clubs.
Both clubs issued a joint statement at the end of United's 2-0 win to condemn the chanting, which related to Leeds fans making aeroplane gestures and singing songs about the 1958 Munich air crash that killed 23 people, including eight of United's legendary Busby Babes team.
United fans responded by chanting "Istanbul" -- a reference to two Leeds supporters being stabbed to death in the Turkish city prior to a UEFA Cup semifinal against Galatasaray in April 2000.
"Both clubs strongly condemn chanting from both sets of fans regarding historic tragedies at today's game," the joint statement said.
"Such behaviour is completely unacceptable and we will continue to work together with our respective fan groups and the Premier League and other authorities on eradicating it from football."
In addition to the statement issued by both clubs, the Premier League added its condemnation.
"The Premier League condemns the chanting heard during today's match between Leeds United and Manchester United," it said.
"The League is treating the issue of tragedy chanting as a priority and as a matter of urgency."
Fixtures between Leeds and United have a long-standing history of trouble between supporters, with the animosity between both stretching back to the 1960s.
But in addition to the chanting at Elland Road, recent Premier League fixtures involving Liverpool have resulted in rival supporters singing songs about the Hillsborough disaster, when 97 Liverpool died in a crush at the 1989 FA Cup semifinal against Nottingham Forest at Sheffield Wednesday's Hillsborough stadium.
Manchester City and Forest fans have both been condemned for chanting about Hillsborough in games against Liverpool this season.
A public announcement was made at Anfield during last month's Premier League game between Liverpool and Chelsea in an effort to stop an anti-gay chant during the match.
But the Premier League's statement has now highlighted the issue of "tragedy chanting," raising the matter as one that is likely to result in measures designed to combat the problem.