Celtic have claimed that their supporters were provoked when involved in a disturbance in Amsterdam on Wednesday afternoon.
Hoops fans were arrested prior to kick-off of the Champions League clash with Ajax after they attacked plain-clothed police officers in Dam Square.
Overall, 44 people were detained by Amsterdam police, including 28 Scots, but Celtic have cried self-defence regarding the attack which reportedly came as a surprise.
"Celtic football club is currently investigating events in Amsterdam last night (Wednesday)," a Celtic statement read.
"We have been informed that there are five individuals detained in Holland. We are not clear if they have any formal association with the Club, however, we will be liaising with the local authorities in Amsterdam, our own police and the British Consulate in order to fully understand events.
"We would stress that there is no excuse for any form of violent conduct.
"In addition, we have received numerous complaints from Celtic supporters in relation to their treatment in Amsterdam, which we will also investigate fully.
"There is no question that Celtic supporters have been subjected to a high degree of provocation. Last week, our supporters were the target of missiles being thrown from Ajax supporters at Celtic Park, a night where 300 seats were damaged within the stadium.
"This was followed up by an organised attack on a group of Celtic supporters in Amsterdam on Tuesday, the night before the match. We have also received numerous individual reports of other attacks on our fans.
"The Celtic travelling support has a magnificent reputation across Europe and our fans have visited major European cities over many years without incident. Once again the overwhelming majority of our supporters behaved impeccably."
