Celtic fans face being banned from attending the Champions League clash at Bayern Munich after the club were hit with a UEFA disciplinary notice.
The Scottish champions were on a suspended ban for away fans following a series of fines over the use of pyrotechnics, and an incident at Villa Park on Wednesday has sparked a potential triggering of the punishment.
Photographs show someone among the travelling support holding a green smoke cannister, which was then thrown on to the pitch during Celtic’s 4-2 defeat by Aston Villa.
A club statement read: “As a result of the use of pyrotechnics during our match against Borussia Dortmund last year, Celtic Football Club was sanctioned by the UEFA Control, Ethics and Disciplinary Body.
“The decision meant that, not only did the club receive a fine of €20,000, but also that, if such behaviour was repeated at a match in the next two years, the club would be prevented from selling tickets to supporters for one away match in UEFA club competitions.
“Unfortunately, the club has received a further disciplinary notice from UEFA following the match against Aston Villa FC on Wednesday evening.
“The club will obviously make robust representations to UEFA and will make every effort to ensure that our fans can attend our next UEFA Champions League match. However, clearly there is a risk that supporters may not be able to attend.
“In light of this situation, it is incumbent on the club to make supporters aware of this risk, when considering making arrangements for travel, until further information is provided by UEFA.”
Celtic are due to play the second leg in the Allianz Arena on February 18-19.