Tokyo police say a metallic drink can that exploded at a train station on Monday may have contained detergent. One person was injured in the explosion.

The can exploded near a ticket vending machine at Nishiarai Station on the Tobu Skytree Line.

A female passenger in her 20s suffered injuries to her forehead and elsewhere. She said she felt hot liquid that came out of the can.

A member of the station's staff who helped the passenger complained of pain in the hands and was treated at a hospital.

Police questioned a 49-year-old man who left the can a few minutes before the incident.

He told investigators he put detergent in a drink can at his workplace with plans to use it at home. He said the explosion was not intentional.

Police are analyzing the liquid to determine what caused the explosion.

The incident came as security in Japan is being tightened ahead of the Group of Seven summit to be held in the western city of Hiroshima this month.