The Hague (AFP) - Rescue workers with sniffer dogs were scrabbling through the wreckage of a three-storey apartment block in The Hague that collapsed after an explosion and inferno in the early hours of Saturday.

The cause of the blast was not immediately clear but police appealed for information about a car seen speeding away from the scene shortly after the explosion.

At least five homes were destroyed in the incident, authorities said, but it remained unclear how many were trapped under the rubble.

Emergency services took four people to hospital in the immediate aftermath of the building collapse, as elite rescue workers trained on recovering survivors from natural disasters scoured the debris.

An AFP reporter on the scene saw dozens of fire trucks as firefighters battled the blaze from the ground and from higher positions. Police helicopters circled overhead.

Debris was strewn across the street and several windows had been blown out, the AFP reporter said. Burned-out cars littered the streets.

Huge plumes of smoke were billowing from a large hole where the building stood, with an acrid smell in the air.

After firefighters had extinguished the blaze, heavy construction equipment moved in to try to clear the rubble.

“I was asleep and suddenly there was this huge bang,” Adam Muller, a 14-year-old local resident, told AFP.

“I looked out of the window and just saw flames. It’s a massive shock,” he added.

- ‘Like an earthquake’ -

Authorities warned locals to keep their windows shut and shut off ventilation systems due to the smoke.

Forensic investigators arrived on the scene to begin to probe a potential cause for the accident, an AFP reporter said.

“Shortly after the explosion, at around 6:15 a.m., a car drove away at very high speed,” police said in a statement.

“The police would like to get in touch with people who saw this car driving or who may have camera footage.”

The three floors of the building consisted of shops on the ground floors and five two-storey apartments, authorities said, with living rooms on the second floor and bedrooms on the top.

The city’s mayor Jan van Zanen travelled to the site to coordinate rescue efforts. He was expected to brief reporters from city hall at 3pm (1400 GMT).

“It was like an earthquake,” said a 53-year-old man who identified himself as Dimi, declining to give his family name.

“Something collapsed but we didn’t see where it came from. I know these neighbours. My kids go to school with them.”

“My new car has also been seriously damaged,” he added.

Hospitals in the area were on standby to treat victims.

Residents told local media the apartment block was mainly inhabited by elderly people and families with children.

Around 40 residents of other blocks near the collapsed building have been evacuated. Some have been taken away by bus to an unknown location.

Prime Minister Dick Schoof wrote on X that he was “shocked by the terrible images of a collapsed apartment building in The Hague.”

“My thoughts go out to the victims, all other people involved and the emergency services who are now working on the scene,” said Schoof.

He said he had been in contact with the city authorities and promised any help necessary.

Dutch King Willem-Alexander wrote on social media: “We sympathise with those personally affected or are worried about their loved-ones.”