Liverpool boss Jurgen Klopp and Manchester United manager Erik ten Hag have called for an end to 'tragedy' chants ahead of Sunday's Premier League clash between the bitter rivals.
Liverpool fans have often chanted about the United players and staff who died in the 1958 Munich air crash.
United supporters have taunted Liverpool with sick songs about the 1985 Heysel tragedy, which saw 39 spectators - the majority Juventus fans - killed at the European Cup final, and the 1989 Hillsborough disaster, where 97 Reds fans died from being crushed at an FA Cup semi-final.
"One of the main reasons why the rivalry between Liverpool and Manchester United is so special is that it is so intense and no-one should ever want to change this," Klopp said on the eve of their latest showdown at Anfield.
"But at the same time, when the rivalry becomes too intense it can go to places that are not good for anyone and we do not need this.
"If we can keep the passion and lose the poison, it will be so much better for everyone."
Ten Hag added: "We all love the passion of the fans when our teams meet, but there are lines that should not be crossed.
"It is unacceptable to use the loss of life, in relation to any tragedy, to score points, and it is time for it to stop.
"Those responsible tarnish not only the reputation of our clubs but also, importantly, the reputation of themselves, the fans, and our great cities."
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