"Stabbing incident with several wounded at the Grote Marktstraat in The Hague. Emergency services are on site," the city's police said on Twitter.
Police later said that three people were wounded in the incident, which came as European cities were on alert after a suspected terror stabbing in London killed two people.
Dutch news agency ANP quoted sources as saying there was "no talk of a terror motive", but there was no immediate confirmation.
Members of the public gathered behind a police cordon on the street, where shoppers had earlier been hunting Black Friday bargains, an AFP correspondent said.
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Police helicopters flew over the scene and several emergency vehicles were on site, the correspondent said.
Police said they were looking for a "slightly dark-skinned man" aged between 40 and 50 wearing a black top, scarf and grey jogging bottoms.
The stabbing was also not far from parliament in The Hague, which is the seat of government for the Netherlands and home to many international organisations.
The incident came hours after a terror-related stabbing on London Bridge in the British capital killed two members of the public. The suspected attacker was shot dead.
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