The Royal Dutch Football Association (KNVB) said it “fully understands” the “disappointment” of the “vast majority of well-meaning Ajax supporters and the travelling FC Groningen supporters”.
“Those who do this are not there for the match or the football. It is sad for those who do support their club, the true supporters,” they said in a statement.
The Eredivisie said there will be “a disciplinary investigation” into the “unacceptable events surrounding Sunday evening’s match”.
Ajax said supporters in the relevant part of the stadium were searched before entry with sniffer dogs also deployed.
“We will, of course, review the camera footage to identify the perpetrators and will also investigate other ways to determine who is responsible,” the Ajax statement added.
“If this leads to the identification of offenders, we will take appropriate measures.”
