Jose Mourinho has called for an end to offensive chants concerning the Hillsborough and Munich tragedies when Manchester United takes on Liverpool on Monday.
Clashes between the two rivals have been marred in recent years by United supporters' songs about the 1989 stadium disaster, which resulted in the deaths of 96 fans, and their Liverpool counterparts' taunts in relation to the plane crash which killed 23 people in 1958.
The two clubs issued a joint statement on Thursday calling for respect between the two sets of supporters ahead of United's latest visit to Anfield.
"In football we have some football tragedies - if you can speak of them like that - which is the big match we lost, some mistake a player did and you can make fun of that in some way," Mourinho told reporters.