At least 42 people are injured  after an explosion  near a restaurant in the northern Japanese city of Sapporo.  A fire that followed reportedly led to a building collapse.

The wounded were  rushed to a hospital , and one person reportedly had serious injuries.  The cause of the explosion is under investigation.

A witness told a Japanese public broadcaster they smelled gas in the area.

First responders warned residents in the area of a possible second explosion.

Additional reporting from  Newsy affiliate CNN