TOKYO (AFP) - A number of people were killed or injured in an explosion at a chemical factory in Japan on Thursday, the police and reports said.

"There was some explosion triggered by some sort of chemical reaction during plant operations," said a police spokesman in Mie, central Japan. "It seems a number of people were killed or injured," he said, adding they were not sure of the exact numbers.

Ms Ranko Hirai, a spokesman for Mitsubishi Materials, said: "We confirmed that there was an explosion at our plant in Yokkaichi, where we produce silicon materials. We have also confirmed that people were injured. We don't know about deaths."

Jiji Press said 15 people were taken to hospital and two of them had died.