Celtic have been fined £420 by Uefa after supporters were alleged to have thrown plastic water bottles towards the San Siro Stadium pitch in Milan.
Two incidents of bottles being thrown towards the pitch were recorded by officials from European football's governing body at the 7 March match.
Neither missile reached the playing surface during Celtic's Champions League defeat by AC Milan.
Celtic are likely to appeal within the three-day limit.
The club claims that the bottles were thrown from an area outwith the official Celtic support.
"The fine of 1000 Swiss francs says it all," said a spokesman.
"Not withstanding this, we are disappointed and may consider an appeal once we have seen the detail.
"We would like to add that, given the last-minute changes to arrangements for the match in Milan, the supporters were once again magnificent."
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