The travelling fans set off fireworks as well as brandishing an 'offensive banner' during December's match at the Stadio Friuli in Italy.

The Scottish club have not appealed the punishment.

"Celtic have been fined 25,000 euros by UEFA's control and disciplinary body for breaching Article 11 of the UEFA disciplinary regulations," a UEFA spokesperson said.

"The decision was taken on February 23. It is nothing out of the ordinary that it wasn't announced then. We can have 100 cases at the monthly meetings. Celtic did not appeal."

The banner was in reaction to a previous charge which saw them fined 12,700 pounds for illicit chanting in their game against Rennes.

Officials at Celtic stressed that the minority responsible were not a correct representative of the club’s support.

"My only surprise is that they got the spelling (on the banner) right," manager Neil Lennon said.

"I am very disappointed, they have let me down, they have let the board, players and background staff down and 99.9 percent of the support down."

Chief executive Peter Lawwell also attempted to distance the club from such fans: "It is very frustrating. Those people are not Celtic supporters.

"We will weed them out and these guys will not get back into Celtic Football Club.

"One or two silly little juvenile boys doing funny kids' pranks and stuff is bringing the whole of Scottish football down."