Celtic chief executive Peter Lawwell has vowed to stamp out pro-IRA chants among supporters after being "inundated" with complaints following the recent defeat at Tynecastle.
Speaking at Friday's AGM at Celtic Park, Lawwell warned fans they were putting the club's reputation at risk. Lothian and Borders Police confirmed they had launched an investigation into allegations of the "singing of sectarian songs" following Celtic's 2-0 defeat by Hearts on October 2.
Lawwell said: "Chants glorifying the Provisional IRA are totally unacceptable. One, it is wrong, and it is an embarrassment to the club and embarrassment to the majority of supporters."
He added: "We were inundated by complaints from our own fans after the game at Tynecastle. 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."
Meanwhile, manager Neil Lennon admitted majority shareholder Dermot Desmond has admonished him over his touchline behaviour, but insists the Irishman is equally passionate about the club.
Celtic shareholders questioned why Desmond did not the AGM, but Lennon revealed he was in regular contact with the billionaire.
"I speak to him at least once a week. He is as passionate as I am. He gives me good advice but has also given me a talking down at times about my behaviour on the touchline or my demeanour.
"I spoke to him yesterday and he was asking about the players coming back from international duty, what condition they were in.
"He is always looking for me to find a different angle, an edge. I guarantee he has the best interests of the team at heart."