At least three people were killed when a truck collided with a barbecue nearby.
Several others were also taken to hospital with injuries after the driver drove through the crowd at the annual party.
Overturned picnic tables were left at the wreckage after tonight’s incident in Nieuw Beijerland in the Netherlands.
It is not clear why the driver, reportedly in shock, headed for the group. He is being questioned by the police.
The truck had a Spanish license plate. Officers believe it was an accident.
The police inform local media that it is still unclear how many people have died, De Telegraaf reports.