Several buildings collapsed in the historic area, leaving at least four people injured. Emergency services said the injured were taken to hospital, while firefighters worked through unstable structures. Dense smoke could be seen rising over the city centre from a distance.
The cause of the explosion was still unknown, and authorities said it was unclear whether others remained trapped.
Streets around the site were sealed off as a precaution. Fire crews used ladders to reach damaged buildings, while broken glass and rubble covered the ground.
Utrecht’s mayor said there was a real concern that people could still be under the debris.
A nearby hospital activated an emergency trauma unit, and the Red Cross asked volunteers to assist.
