Liverpool and Manchester United managers Jurgen Klopp and Erik ten Hag have called for an end to "tragedy chanting" in a joint statement.
The two sides meet at Anfield on Sunday and Ten Hag called their rivalry "one of the greatest in world football".
It has occasionally been marred by rival supporters chanting about the Munich air disaster and the Heysel and Hillsborough tragedies.
But Liverpool boss Klopp told fans to "keep the passion and lose the poison".
Ten Hag added: "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.