The Portuguese would not go into detail when asked to explain the falling out in the immediate aftermath of his side's 2-1 loss at Old Trafford on Sunday afternoon.
Reports in the British press suggest that Mourinho triggered a 20-man melee by entering the City dressing room after taking offence at the over-the-top celebrations, which Citizens boss Pep Guardiola has since defended.
Speaking ahead of United's home match against Bournemouth on Wednesday evening, Mourinho initially batted away questions regarding the incident, before adding: "For me it was just a question of diversity – diversity in behaviours and diversity in education. Just that and nothing more than that."
United and City are being investigated by the Football Association, but the incident will not be looked into by Greater Manchester Police as no formal complaints were made.