"There are between 12 and 20 dead," a police official at the eastern town of Eupen said.
The blast took place at 5.30pm at a Fina station owned by Belgian oil company Petrofina near a restaurant. About 30 people, mainly truckers waiting for customs clearance, were in the restaurant. Several injured people were taken by helicopter across the German border to Aachen for medical treatment.
Belgian television showed a mass of twisted metal in the burned-out building, whose roof had collapsed. Rescue workers sifted through rubble as smoke billowed around the blackened petrol station. An officer at the Belgian Interior Affairs Ministry said the cause of the blast was not yet known but first indications were that a small natural gas container exploded.
"The cause was accidental, not a bomb or a criminal intention," a police officer said, four hours after the accident, as police sifted through the rubble looking for bodies. "By now it is useless to look for survivors, only victims." He said that some of the people were so badly charred by the fire that they could not be recognised.
The national news agency Belga said earlier that a motorway near the Flemish town of Courtrai in northwest Belgium was closed because of fears that a bomb had been placed in a Royal Dutch/Shell petrol station in protest against the planned dumping of the Brent Spar in the Atlantic. A bomb warning later proved to be false.Reuse content