Several houses have collapsed and many windows in the central parts of the city were shattered by the blast wave, reported the Dutch news agency ANP.
Several hours after the blast, only four people had been taken to hospital and no deaths had been reported. But the search for more injured people in the rubble is expected to continue at least through the evening.
The cause of the explosion is unclear. Firefighters were unable to reach the location of the explosion due to the risk of landslides and the heat from the fires.
