Celtic's visit to Dinamo Zagreb in the Europa League has been marred by reports that police clashed with Hoops fans at the Maksimir Stadium.
The travelling supporters are said to have let off flares in the away section of the ground and local law enforcement allegedly used CS spray to subdue them.
Photographs of a bright red flare lighting up the Celtic section of the stadium and police dressed in full riot gear arriving on the scene are in circulation on Twitter.
Celtic crashed to a 4-3 defeat in Zagreb, but progressed to the next phase of the competition as Group D runners-up.
