Four people have been injured following a stabbing in central Amsterdam, police say.
The suspect, who has been arrested and will be questioned later on Thursday, was overpowered with the help of a local resident and taken to hospital with a leg injury, police say.
A small area of the central Dam Square remains cordoned off for forensic investigation.
Dutch police say they do not have any details on the condition of the four injured people, and the motive for the incident remains unclear.
Video posted on social media showed a helicopter landing in front of the Royal Palace in Dam Square and emergency vehicles also inside a cordoned-off area.
Early images showed a person on a stretcher being loaded into the back of an ambulance.
A witness told the Dutch paper De Telegraaf that they suddenly heard an “icy scream” and after that panic broke out in the area.
A shop assistant also said that she heard a lot of shouting and screaming and that people started running, the paper reported.
Witnesses quoted by local media said a girl and an elderly woman were stabbed, although this has not been confirmed by police.
Earlier, a police spokesperson told Dutch media there had been reports of a robbery.
Police had initially said that five people were injured in the stabbing, but in an update said one of the injured was the suspect.
They are urging anyone with images of the incident to upload them as evidence.