An explosion has hit crime laboratories in a Brussels suburb in what police are treating as a criminal but not terrorist incident.

Shortly before 02:30 local time (00:30 GMT), a car rammed through three fences, leading to an explosion and a large fire, RTL Belgium reported.

Belgian media said "one or more" suspects then reportedly set off a bomb near the laboratories.

But police could not confirm that a bomb had exploded.

Belgium's terror alert level remains high since bomb attacks on Brussels airport and the city's metro, claimed by so-called Islamic State, that killed 32 people in March.

There were no casualties in the latest blast, Belgian media reported, and it is unclear what happened to the perpetrators.

Fire service spokesman Pierre Meys told Agence France-Presse that the "extremely powerful" blast "was probably not accidental".

Some 30 firefighters helped put out the resulting fire at the National Institute of Criminology, which media said suffered "significant" damage.

Prosecutors said an investigation was now under way.

Forensic analysis linked to criminal cases is carried out at the site, but RTL report that it is not the only laboratory of its kind linked to the police.

Images submitted to RTL by nearby residents showed flames and heavy smoke rising into the night sky.

The independent institute, linked to Belgium's federal justice body, is in Neder-Over-Heembeek, a suburb in the north of Brussels.

Bilal Hadfi, who blew himself up outside the Stade de France during last November's Paris attacks, lived in the suburb.