Shakhter Karagandy have been warned by Uefa that if they continue to slaughter sheep before a game they will face possible sanctions.
The Kazakh champions courted controversy ahead of the first leg of their Champions League play-off against Celtic last week when they performed a ritual killing of a sheep the day before the clash.
Ahead of the second leg of the tie against Neil Lennon's men on Wednesday, which Shakhter lead 2-0, a letter written by Uefa competitions director Giorgio Marchetti to the club's executive director Yerden Khalilin was released.
"We were informed that an animal slaughter took place at some point prior to the Champions League fixture involving Shakhter Karagandy and Celtic at the Astana Arena on Tuesday 20 August 2013," wrote Marchetti.
"Although certain practices may be culturally rooted, they have no place in or around a sporting arena or event.
"In this context, I would like to make you aware that animal slaughter on a football pitch or in a stadium before, during or after a Uefa competition match - or with reference to a Uefa competition - is totally improper, and will not be tolerated.
"In case of re-occurrence, it will inevitably lead to a full investigation by our disciplinary bodies."
The practice led to outrage from leading animal rights groups, with People for the Ethical Treatment of Animals (Peta) writing an open letter to Uefa president Michel Platini demanding action.
European football's governing body has now responded to those concerns, threatening disciplinary proceedings should the practice be repeated.