A so called 'ghost driver' reportedly crashed directly into another vehicle, pulling three other cars into the wreckage as well.
The accident took place on the E42 road between Namur and Mons, near the town of Spy.
The ghost driver is reportedly severely injured, and media reports say the state of the passengers in the other vehicles is not yet known.
The accident seriously disrupted traffic as reports say there are currently several kilometres of traffic jams.
Traffic authorities temporarily closed-off the road and deviated incoming traffic to a nearby road exit.
The Brussels Times