It may have consequences for Feyenoord that there were supporters who entered the stadium during the home game against RKC Waalwijk (3-0) on Sunday.

The KNVB prosecutor for professional football started a preliminary investigation on Monday, a spokesperson told NU.nl.

With about twenty minutes to go, Feyenoord-RKC was briefly shut down by referee Bas Nijhuis when a group of fans appeared in the stands and lit fireworks, torches and smoke bombs.

Fireworks also landed on the field.

After a delay of a few minutes, the game could be resumed.

The players of Feyenoord created a remarkable image by walking in the direction of the supporters and clapping in front of them.

It was already known at Feyenoord that supporters would come to the stadium.

However, it is unclear how the group of supporters managed to enter De Kuip.

No arrests were made.

Feyenoord captain Steven Berghuis took it up for the supporters after the game.

"It is from a positive point of view, I think," he said.

Trainer Dick Advocaat was less happy with the action and said he was shocked.

Both Feyenoord and RKC did not play for anything anymore.

The team from Rotterdam will enter the play-offs for European football as number five in the Eredivisie, in which Sparta Rotterdam is the opponent on Wednesday during the semi-finals.

The players of Feyenoord applauded the action of the fans.

The players of Feyenoord applauded the action of the fans.

Photo: Pro Shots