The mayor of Mogadishu was severely injured when a suicide bomber attacked his office, killing several people on Wednesday, the Somali police told AP. Mayor Abdirahman Omar Osman and his deputy have been hospitalised. Two district commissioners were among those killed, said Police Captain Mohamed Hussein.

The blast took place soon after United Nations envoy to Somalia James Swan had made a visit to the mayor’s office. It is still unclear how the suicide bomber was able to get into the mayor’s office during a security meeting. Officials in the United Nations told AFP that Swan had left before 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,” AFP quoted Mahdi Abdirahman, a security official, as saying.

“The blast was very heavy, and I saw people, fleeing some with shrapnel wounds outside the Banadir administration headquarters,” said Mohamud Shariif, a witness.

The Al-Qaeda-linked Al-Shabab terror group has claimed responsibility for the attack. Mogadishu is frequently attacked by the terror group, which has attempted to topple the government in Somalia for a decade.