Police, firemen search for cause of explosion in Japan's Sapporo

Firefighters operate at the site where a large explosion occurred at a restaurant in Sapporo, Hokkaido, northern Japan, in this photo taken by Kyodo December 16, 2018. Mandatory credit Kyodo/via REUTERS

TOKYO (Reuters) - Police and fire officials on Monday were searching for the cause of a dramatic explosion in the northern Japanese city of Sapporo that collapsed a building and injured 42 people.

Media reports said the Sunday night incident may have involved propane gas tanks in the building where the blast occurred. Sapporo police and fire officials said it was too early to say anything certain about the cause of the explosion.