Volkswacht Bodensee - 'Gigantic explosion', fire in Dutch city of Utrecht, four hurt

"As far as we know now, there are four victims: two people treated by paramedics at the scene, one taken to hospital with minor injuries, and another who became unwell after the events," Sharon Dijksma told reporters.

"Fortunately, according to initial reports, there is no one seriously injured directly by the explosion," she added.

After several hours, firefighters succeeded in extinguishing the blaze that broke out at around 3:30pm (1430 GMT) following what emergency services described as a "gigantic" explosion.

Authorities are still investigating the cause of the blast but a gas leak is the main hypothesis -- no foul play is currently suspected.

Several buildings collapsed right in the historic heart of Utrecht, with firefighters waiting for the all-clear before searching debris for potential victims.

However, no one has been reported missing and authorities believe the buildings were empty at the time of the explosion.

An AFP reporter on the scene saw several firefighters with ladders trying to access buildings.

Shattered glass littered the streets that were cordoned off to the public, according to this reporter.

After the explosion, TV images showed a plume of smoke rising above the ancient city centre and rubble strewn across the streets.

"I knew right away that this was bad," NOS quoted one witness, Margot Schroevers, as saying.

"The ground was shaking," she said.

F.Fehr--VB