Celtic could incur the wrath of UEFA after Strathclyde Police alerted European football's governing body of chants made by fans in their recent home Europa League game against Rennes.
UEFA have now opened a disciplinary case against Celtic over 'discriminatory chanting'.
"We can confirm there were a number of instances during the game of singing offensive songs and inquiries are ongoing to detect the offenders," a spokesperson for Strathclyde Police said.
Hoops fans have been urged to stop singing pro-IRA chants after the club was "inundated" with complaints made by their own fans at Hearts.
"It is wrong, and it is an embarrassment to the club and embarrassment to the majority of supporters," Celtic chief executive Peter Lawwell added.
"We have dealt with it at Celtic Park and we will do all we can to make sure it doesn't happen home or away.
"We don't want it, we don't need it. We have the best supporters in the world and hold that reputation dear."
The case will reportedly be heard on December 8.
