Terror fears were sparked this morning after attackers rammed the Brussels Institute of Criminology with a car before the building was ravaged by fire and explosions.

A vehicle carrying two people is said to have forced its way onto the site in northern Brussels before the attackers scaled a ladder and launched an arson attack.

Thick black smoke was seen coming from the laboratories at about 3am this morning and residents reported hearing a loud blast sparking fears of a bomb.

The building was empty and no one was wounded. Local investigators believe the arson attack may have been an attempt to destroy evidence held in the building. The car was torched by the attackers.

Five people were arrested nearby and are being held and questioned, a spokeswoman for the city's prosecutors said.

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Terror fears were sparked this morning after attackers rammed the Brussels Institute of Criminology with a car before the building was ravaged by fire and explosions

Local investigators believe the arson attack may have been an attempt to destroy evidence held in the building. The car was torched by the attackers

Five people were arrested nearby and are being held and questioned, a spokeswoman for the city's prosecutors said. Forensics work at the scene

Damage: Fire and explosions caused extensive damage at the Brussels Institute of Criminology in the north of Brussels

Forensic investigators have been called to the scene as an investigation gets underway

Prosecutors have opened a investigation into 'deliberate arson of a building and damage by explosion', while bomb disposal experts attended the scene.

The institute, which is in the Neder-Over-Hembeek suburb of northern Brussels, assists and advises Belgium's justice authorities in carrying out their inquiries.

Eyewitnesses reported seeing thick black smoke coming from the building before fire crews descended on the scene in the early hours of the morning.

As the investigation got underway this morning, prosecutors said reports of a bomb were probably false and that the incident was more likely an arson attack designed to destroy criminal evidence.

'It's probably not terrorism. It's a criminal act,' said spokeswoman Ine Van Wymersch. 'I cannot confirm that there was any bomb.

'With a fire you get explosions, but it's not that explosives were thrown inside or installed.'

When asked whether the attack could be terrorism she said: 'It is a path we are looking down. 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.'

State broadcaster RTBF and other outlets had reported that a car drove through a security barrier at the site followed by an explosion.

As the investigation got underway this morning, prosecutors said reports of a bomb were probably false and that the incident was more likely an arson attack designed to destroy criminal evidence

Dozens of fire fighters and police officers were called to the scene of the fire this morning

Eyewitnesses reported seeing thick black smoke coming from the building before fire crews descended on the scene in the early hours of the morning

A car with two people on board forced its way onto the site before the attackers scaled a ladder and attacked the building

The institute, which is in the Neder-Over-Hembeek suburb of northern Brussels, assists and advises Belgium's justice authorities in carrying out their inquiries. Police cordoned off the area after the attack

Investigators said the suspected arsonists set fire to a laboratory used to analyse DNA samples found at crime scenes.

'So it's an act that could be linked to (destroying) several files,' Van Wymersch said.

She said any explosion heard by residents may have been caused by material being consumed in the fire.

Fire service spokesman Pierre Meys said there was an 'extremely powerful' explosion, adding: 'Windows of the lab were blown out dozens of metres away.'

He said about 30 firefighters were at the scene at around 3am fighting the blaze.

A young woman living in the neighbourhood said the explosion woke her up. 'It made the house shake.'

Belgium has been on high alert since a March 22 attack on the Brussels airport and tube network killed 32 people.

Those attacks were claimed by ISIS, which controls large areas of territory in Iraq and Syria and has claimed numerous terror atrocities in Europe in recent months.

The jihadist cell responsible for the Brussels attacks was also heavily involved in the November Paris attacks in which 130 people were killed and hundreds more wounded.

Fire service spokesman, Pierre Meys, said this morning that the incident 'was probably not accidental'

A car rammed through the barriers at about 3am before the laboratories were torched

Under attack: The Brussels Institute of Criminology in the north of Brussels, assists and advises Belgium's justice authorities in carrying out their inquiries

The bombmaker for the Paris attacks, Najim Laachraoui, blew himself up at Brussels airport.

Earlier this month it emerged that Belgian authorities were also hunting a cousin of the El Bakraoui brothers who also blew themselves up in the Brussels attacks.

Belgium has caught several people linked to the Brussels and Paris atrocities including Salah Abdeslam, the last surviving member of the Paris IS cell, who has since been extradited to France.

In June Belgian authorities approved a French extradition request for Mohamed Abrini, the 'man in the hat' seen on CCTV footage with Laachraoui and Ibrahim El Bakraoui at Brussels airport.