A suicide bomber reportedly entered a hall and detonated a bomb where officials were meeting, wounding Mogadishu's mayor and other top officials.
At least six people were killed when a suicide bomber targeted offices of Mogadishu mayor, Somalian government said on Wednesday.
"Six people, including two district commissioners and three directors, were killed in the terrorist attack this afternoon, six others have been wounded among them the mayor of Mogadishu and other district commissioners who are now being treated by the medical team," Information Minister Mohamed Abdi Hayir Mareye told reporters.
A security source, who asked not to be named, said a suicide bomber had entered a hall where the officials were meeting and detonated the bomb inside.
Earlier United Nations special envoy James Swan had met with the mayor, Abdirahman Omar Osman, at the headquarters of the Banadir district, which encompasses Mogadishu, according to the mission's Twitter account.
However UN sources told AFP he had left by the time of the explosion.
"The blast occurred inside but we are not sure what exactly caused it, some reports we are getting indicate it was caused by a suicide bomber ... and there are casualties," said security official Mahdi Abdirahman.
He did not give further details on the wounded.
"The blast was very heavy, and I saw people fleeing, some with shrapnel wounds outside the Banadir administration headquarters," said witness Mohamud Shariif, referring to the regional government offices.
Al Shabab — which has fought for more than a decade to topple the Somali government — regularly carries out attacks in Mogadishu.
The city was struck by a car bomb on Monday, which left 17 dead and more than two dozen wounded.