A car ploughed into a parade that included Queen Beatrix and the Dutch royal family today, killing four people and injuring 13, Dutch officials said.
Five of the injured are in a serious condition, but no royal was hurt in the deliberate attack by a 38-year-old Dutchman on the Queen's Day holiday, police said in the town of Apeldoorn.
Television footage showed a small black Suzuki with a crumpled front driving at high speed after ploughing through a crowd of spectators.
It missed an open-top bus carrying Queen Beatrix and the royal family by four or five metres, before finally crashing into a stone monument.
In the bus, Princess Maxima, wife of heir Willem-Alexander, looked on in horror after the car hurtled through the crowd in the centre of the city, about 90 km (56 miles) east of Amsterdam.
"What started as a beautiful day has ended in terrible drama, wich has shocked us deeply," Queen Beatrix said in a response, which was broadcast on national television.
The driver of the car, who was injured, was detained.
"So far we have no indication that there is a link to terror (activities)," public prosecutor Ludo Goossens told a news conference.
The government cancelled the remaining official activities on the annual national holiday.