At least 15 people have been killed and another 200 injured in the explosion of a natural gas pipeline at an industrial park, 30 kilometers south of Brussels. Belgian authorities say the casualty toll is certain to rise.

The explosion shook the ground for several kilometers, and scared residents of nearby towns. Pierre Lardinois, who lives three kilometers from the site of the blast, says he thought it was an earthquake.

Mr. Lardinois's neighbor, Alain Spiteri, said the noise was frightening.

He, too, thought it was an earthquake. He saids he saw flames rise dozens of meters into the sky, and, he said, he thinks they could be seen for at least 30 kilometers around.

The explosion came minutes after police and firefighters arrived on the scene to probe a reported leak in the gas line at the Ghislenghien industrial park, near the town of Ath. Thierry Silien, a local police officer, describes what happened.

He said that flames from the blast rose at least 100 meters into the sky, intense heat spread over a kilometer-wide radius and that the noise caused by the fire was deafening.

Officer Silien also said that many of his colleagues in the police and fire departments were among the casualties

The authorities rolled out an emergency disaster plan involving army helicopters and ambulances from throughout Belgium and northern France to help ferry victims to hospitals. A Health Ministry spokeswoman said that at least half of the injured suffered serious burns.

Guy Petit, the acting governor of Belgium's Hainault province, where the blast occurred, says it is too early to say what the final casualty toll will be, because emergency crews are still trying to recover bodies at the explosion site.

The blast was Belgium's worst industrial disaster in at least 20 years. Prime Minister Guy Verhofstadt interrupted his vacation in Italy to fly to the scene of the explosion.