Celtic could face the prospect of more UEFA sanctions after their fans waved Palestinian flags at their Champions League qualifier against Hapoel Be'er Sheva on Wednesday night.
Fans housed where the new safe standing area is at Celtic Park - the Green Brigade group - displayed the flags during the 5-2 win for Brendan Rodgers' side.
UEFA forbids political expressions in football and given their opponents were Israeli, the body could take the view the act of waving Palestinian flags was a provocative gesture.
Celtic have already been punished by European football's governing body eight times in less than five years for a variety of offences.
On one of those occasions, they were fined £16,000 by UEFA after Palestinian flags were waved at another Champions League qualifier against Icelandic side KR Reykjavik in July 2014.
In total, Celtic have been fined £123,000 for a range of misdemeanours at European ties including the use of flares, prohibited banners, unacceptable crowd behaviour and improper team conduct.
If charged and found guilty, Celtic could face the part-closure of their stadium for a future European fixture.