Rangers have condemned a bottle-throwing incident and an “unacceptable” tifo display from their supporters at Sunday’s Old Firm fixture at Ibrox.
A glass bottle was among several items thrown into Celtic goalkeeper Viljami Sinisalo's penalty area in the second half of the 1-1 draw.
And prior to the match a banner was unfurled in the Copland Stand which depicted iconic former Rangers player and manager Graeme Souness holding a shotgun, with the words "Take aim against the rebel scum" underneath.
Rangers have admitted the display "crossed a line".
A Rangers spokesperson said: "Rangers Football Club condemns the actions of the individual who threw a bottle during today's match. This behaviour has no place at our stadium. Steps have already been taken to identify the person responsible, and the club will take the strongest possible action once their identity is confirmed.
"We also acknowledge that the tifo displayed prior to kick-off crossed a line and was unacceptable.
"Our approach to supporter displays has always been built on trust, with the responsibility placed on groups to exercise good judgement.
"We will reflect on how these displays are managed and engage with supporter groups to ensure the right balance of trust, responsibility and oversight is maintained moving forward.
"Rangers is proud of its passionate fanbase, and we all share a duty to protect the standards and reputation of our club."
Sky Sports News has contacted the Scottish FA and the SPFL for comment.
