An explosion in a downtown Tokyo building has injured four people, according to media reports

TOKYO -- An explosion at a building in Tokyo’s Shimbashi commercial district on Monday shattered windows and spewed smoke, injuring four people, department officials said.

Tokyo Fire Department said the explosion occurred at an eatery on the second floor of an eight-story building, injuring two people inside and two pedestrians who were hit by shards of glass.

Fire department officials said the four injured were all conscious but further details were unknown. NHK national television said three of them were seriously injured.

An owner of the eatery who was among the injured told police that he noticed a smell of gas or sewage when he entered a smoking room, and the explosion occurred when he flicked his lighter, NHK said.

No other information was yet available.