The blast also damaged nearby houses, blew off the roof of a mosque and caused a nearby school to collapse, BBC reported.
Police officer Abdullahi Hussein said a suicide bomber had rammed a car into the district office in Howlwadag district.
The militant group al-Shabab, which has waged an insurgency for more than 10 years, has claimed to be behind the attack.
In a similar incident on July 14, seven people were killed and several others injured in two explosions near the presidential palace in Mogadishu.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
