The KNVB has released a statement strongly condemning the incidents which took place in the match between Feyenoord and Ajax including when Davy Klaassen was struck in the head by an object from the crowd.
The national governing body released the statement after De Klassieker was suspended twice following incidents involving the fans at De Kuip.
First, the match was suspended seconds after kick-off after a huge fireworks display forced the referee to stop play before making sure it was safe to restart.
The second incident saw midfielder Klaassen, 30, struck with an object shortly after scoring the eventual winner to secure a place in the KNVB final with rivals PSV Eindhoven.
With Klaassen on the floor waiting to receive treatment, Feyenoord assistant coach John de Wolf took to the microphone to send a stern message to the home supporters after the object appeared to come from the home end.
KNVB confirm an investigation is underway but warned anyone who condones this sort of behaviour and is looking to cause further disruption in football matches should refrain from attending in the future.
The statement reads: “Tonight during the semi-final of the cup tournament, we saw that a player was injured on the head because someone in the audience threw an object at the field. This despite the precautions, such as nets in various places in the stadium.
“Recently a player was beaten by a supporter and now another low point has been reached. Thousands of people go to the stadium to watch the players play football. Then it is insane that they are apparently not safe on the field.
“Of course clubs and organisations take precautions, but it starts with the intentions of the perpetrators. If you don’t come to the stadium for football, but to riot, then stay away: football, the clubs, the real supporters and the players are better off without you.
“Naturally, tonight’s events are being investigated, with the common goal of punishing the perpetrators.”
