Suicide bomber gets a second try
A suicide bomber sent back to his car to disarm the device by Somali police detonated it instead and killed four people.
The blast was near the former Egyptian Embassy in Mogadishu.
Officer Abdi Hassan said a would-be suicide car bomb was intercepted hours before the blast and the bomber arrested.
But Hassan police returned him to his vehicle under orders that he disarm the explosives. Instead, he was able to trigger the bomb.
Police commanders did not answer phone calls seeking comment after the blast. One police official said that supervisors told them no one was to talk to journalists about the explosion.
Al-Shabab militants have stepped up a campaign of roadside bombs and suicide car bomb attacks in Mogadishu in recent weeks. The militants were almost entirely pushed out of the Somali capital earlier this year in an offensive by African Union forces.