There have been 15 arrests made and eight police officers injured following violence in Amsterdam's city center prior to the Scottish club's defeat to Ajax in the Champions League.
Amsterdam Police confirmed a group of Celtic fans attacked plainclothes police officers with bottles and sticks before their side’s Champions League defeat to Ajax.
"There were 15 arrests, mostly Celtic supporters," said a police statement. "At the end of the afternoon, a large group of Celtic supporters attacked police officers in plain clothes. Eight were injured and one left unconscious."
Around 12,000 Celtic fans were expected in Amsterdam, although the club warned supporters not to travel to the stadium if they did not have a ticket.
The Scottish side also urged supporters to be “extra vigilant” after nine Ajax fans were arrested after attacking Celtic supporters on Tuesday evening.
A club statement 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.
“The attack in the city center by an element of the Ajax support resulted in a number of arrests.
“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.”