Sapporo: More than 40 people were injured in a major explosion in the Japanese city of Sapporo. Initial reports have suggested a gas blast. The actual cause of the explosion that occurred on Sunday is not yet known.

Reports state that the are affected had both residential and dining establishments. Here was a thunderous sound and the blast shattered the windows of the structure across the building and sent tremors down the street. Residents smelt gas after the explosion and debris was scattered across the street.

More than the 20 fire engines were deployed. Firefighters doused the remnants of the building with water. Reports also that the police have warned that there could be another explosion in the area.

The injured were rushed to nearby hospital. Among the 42 who were injured, one person was said to be in a serious condition.

Police personnel and firemen are still trying to determine the cause of the explosion.

Sapporo, with almost 2 million people, is on Japan's large northern island of Hokkaido.