An explosion in the Hague caused the front of a building to collapse, local media reported on Sunday.
The city's aviation police tweeted that the explosion may have been a gas explosion.
RTL News said that a blast of unknown origin had caused "houses to collapse" and that people might be trapped under the rubble.
A story and photograph published by local news service Omroep West said a single building had collapsed after a blast and emergency services were at the scene.