A car bomb went off on a busy street in the Somali capital Mogadishu on Sunday, a police officer said, while a Reuters witness said the blast was followed by big clouds of smoke visible in sky.

The bomb exploded as the car was driving in the busy Maka al Mukaram road, the police officer told Reuters. "It is a busy area. We do not yet know the figure of casualties," the police officer, Major Hussein Nur, said.

A Reuters reporter at the scene of the blast counted four bodies lying on the ground. Photographs taken by Reuters showed three destroyed cars on the road, with two still burning.

It was not clear who was responsible for the blast.