Celtic are considering legal action against fans who set off flares in Turkey after UEFA opened fresh disciplinary proceedings.
The club have issued indefinite bans to two supporters following incidents during their final Europa League game of the season, last Thursday's 1-1 draw against Fenerbahce.
Celtic have been hit with two charges by UEFA, one for the lighting of fireworks by away fans and another for improper conduct of the team, which was automatically sparked by their card count of five yellows.
A club statement read: "As part of our ongoing investigation into the recent match against Fenerbahce in Istanbul and the use of flares within the stadium, Celtic today confirmed that it has indefinitely suspended two individuals from attending all Celtic matches, home and away.
"There have been calls from many for Celtic to raise a civil action in relation to recovering any fines imposed and this is something which the club will consider.
"Celtic has repeatedly stated its strong opposition to the use of flares but regrettably again, a very small number of individuals have damaged the club they claim to support, resulting in a further UEFA charge.
"Celtic supporters travel in their thousands to European matches and the club is always grateful and proud to have such a magnificent following from fans who have earned such a wonderful reputation.
"However, we cannot allow the club and our supporters to be damaged reputationally or financially any more, by a handful of individuals.
"While we await UEFA's determination, we have been inundated with support from Celtic fans who want an end to this activity and, like the club, do not want those responsible associated with Celtic in any way."
Celtic were hit with a €10,000 fine for an identical charge sheet following their defeat by Inter Milan in Italy earlier this year and the latest case will be the eighth time in five seasons that they have punished by the European governing body for supporter incidents.
The latest case is due to be heard by UEFA's disciplinary committee on Feb. 18.