A suicide bomb attack on the local government headquarters injured the mayor of Mogadishu and several other Somali officials on Wednesday, a relative of one of the victims told Reuters.
No one immediately claimed responsibility but Al Qaeda-linked Islamist group al Shabaab, which wants to topple the UN-backed government, regularly carries out such attacks.
"A suicide bomber walked into the meeting hall and blew up himself," said Mohamed Abdullahi, adding that his cousin and the mayor were among the officials injured.
The area was filled with ambulances after the blast, shopkeeper Mohamed Osman said.
There were no immediate details about casualty numbers, after the government authorities told medical personnel not to disclose figures as they have done in the past.
Journalists are forbidden from going to attack sites.
Somalia has been riven by conflict since 1991, when clan warlords overthrew a dictator, then turned on each other.