A huge explosion and fire at a restaurant in the Japanese city of Sapporo has injured at least 40 people, with one of them in serious condition.<br />The cause of Sunday's incident is not yet known, but reports suggest a gas leak may be to blame.<br />A building in the Toyohira district has collapsed due to the subsequent fire and images show the building's remnants scattered across the street.<br />Police have sealed off the area amid fears of further explosions. <br />
