An explosion was reported at the Brussels Institute of Criminology in the north of Brussels on Monday but the building was empty and no one was wounded.

A car rammed through the barriers at about 3 a.m. local time and set fire to the laboratories.

Police have been deployed and sealed off the area.

Ine Van Wymersch, a Brussels prosecutor, told Reuters: "It was arson, deliberate arson at the laboratory of the federal police," she said. "With a fire you get explosions, but it's not that explosives were thrown inside or installed."

"It is a path we are looking down," she said, referring to the possibility of militant involvement. "But certainly not the first one we are thinking about. We are thinking more of deliberate arson by organised crime. We have no indications that it was terrorism," she said.

The lab is based in a suburb north of Brussels called Neder-Over-Hembeek.

The institute carries of carries out forensic investigations in criminal cases and is tied to the Ministry of Justice, according to a report in the Guardian.

The Belgian city of Brussels, which houses the main administrative buildings of the European Union, has been on high alert since March, when 32 people were killed in a co-ordinated terrorist attack on its airport and underground train network.

An earlier version of this story said that a bomb had exploded at the institute.