Celtic fans have been warned to be extra vigilant before, during and after tonight's UEFA Champions League match with Ajax in Amsterdam.
The official club warning comes after an unprovoked attack on a number of supporters in a city-centre bar on Tuesday evening which resulted in a number of arrests.
Dutch police had been on the look-out for trouble after several incidents in Glasgow before the sides' previous meeting on October 22.
Pubs frequented by Celtic fans were targeted by their Dutch counterparts on the Monday before the game, and there was trouble in and around the city centre leading up to the match itself.
During the tie, which Celtic won 2-1, a section of the travelling support smashed seats in the away end of the ground before hurling them towards Celtic fans after James Forrest's opening goal.
In a statement, Celtic said: "Celtic Football Club is urging all supporters in Amsterdam for tonight's UEFA Champions League tie with Ajax to be extra vigilant following an unprovoked attack on Celtic fans last night.
"Celtic are urging all supporters to be extra vigilant in the city centre and at the Amsterdam ArenA, and to only stick to the advised areas for safety reasons."
And the unrest was further intensified by the arrival in the city of a group of Dinamo Zagreb fans who are in the country for Thursday's Europa League tie against PSV Eindhoven.
Supporters of Dinano have caused trouble in the city before and a spokesman for Amsterdam Police said: "We shall do everything to prevent supporters of the three clubs meeting."
Meanwhile, UEFA officials have decided to play this evening's Group H encounter under a closed roof at the Amsterdam Arena due to the threat of rain.
The Celtic trio of Georgios Samaras, Kris Commons and Mikael Lustig have all travelled and are expected to start the match.
Samaras and Commons have been sidelined with knee and hamstring injuries respectively whilst manager Neil Lennon will check on the fitness Lustig, who has a long-standing hip problem, before finalising his starting line-up.
Skipper Scott Brown is suspended so Beram Kayal will again deputise in midfield.
You can watch the action unfold as Celtic aim to maintain their interest in the competition live on Sky Sports 4 from 7.30pm tonight.