Several people have been shot, and three confirmed dead, in a tram in the central Dutch city of Utrecht.
Monday’s shooting was described by Dutch police as having a “terrorist motive”.
They said the suspected gunman was at large, prompting the authorities to raise the terrorism threat to its highest level in Utrecht province.
Schools were told to shut their doors and paramilitary police increased security at airports and other vital infrastructure.
Security was also stepped up at mosques.
The Utrecht police said The October 21st square, a tram station stop outside the city center, had been cordoned off as emergency services were at the scene.
Helicopters were rushed to the scene as no arrests were made, a police spokesman added.
Local broadcaster RTV Utrecht quoted a witness as saying he had seen a woman lying on the ground amid some kind of confrontation and several men ran away from the scene.
Prime Minister Mark Rutte said he was deeply concerned about the incident and convened crisis talks.
The incident comes after a lone gunman killed 50 people in mass shootings at two mosques in the city of Christchurch, New Zealand, last Friday.
Utrecht, the Netherlands’ fourth largest city, is known for its picturesque canals and large student population. Gun killings are rare in Utrecht, as elsewhere in the Netherlands.