The Rangers training ground has been vandalised with vile graffiti ahead of the Old Firm clash.
The derogatory slur "f*** huns" was daubed across a sign at the entrance to the Hummel Training Centre at Auchenhowie.
Furious football fans shared images of the graffiti on social media this morning.
It is understood the graffiti has now been cleaned.
Rangers prepare to face Celtic in the Betfred Cup Final at Hampden tomorrow.
Earlier this week we told how Rangers captain James Tavernier was struck by a pie at Pittodrie.
Aberdeen confirmed they are investigating the incident.
A Police Scotland spokesperson said: “We received a report of vandalism to the front gate at Murray Park around 1am on Saturday, 7 December, 2019.
“Enquiries are ongoing. Anyone with information about this incident should contact police on 101, quoting incident number 0298 of Saturday, 7 December, 2019.”