A policeman and 15 civilians have been killed in a suicide car bomb attack in the Somali capital, Mogadishu.
The city’s governor said the bomb was detonated at a police checkpoint, about 200m from a look-out post belonging to the African Union peacekeeping mission.
Mohamed Osman Ali described the attack as a “massacre”, but said it was not immediately clear who was responsible.
The AU mission is guarding Mogadishu’s presidential palace, but most of the city is controlled by Islamist rebels.
Last month, President Abdullahi Yusuf Ahmed resigned after months of government infighting. The Somali parliament is due to choose his replacement on Monday at a meeting in neighbouring Djibouti.
Mr Ali said a policeman manning the checkpoint on the Makka al-Mukarama road in Mogadishu had fired at the car when it approached at high speed.
The bomber then crashed his car into a local bus and detonated a bomb, he said.
Hospital sources say 38 people were severely injured by the blast, some of them critically.
It is not clear whether the attacker had been targeting the African Union Peacekeeping Mission in Somalia (Amisom) post not far beyond the checkpoint.
An Amisom spokesman, Maj Barigye Ba-hoku, appeared to blame the Islamist rebel group, al-Shabaab, which is attempting to topple the government.
“That opposition group has massacred only innocent Somali people,” he told Reuters news agency.
However, fighting broke out not long after the explosion between Amisom troops and those of the government.
Officials in Somalia’s government recently warned of a security vacuum caused by the withdrawal of Ethiopian troops this month.
The US wants the United Nations to take over peacekeeping duties from the African Union, which only has a small force in the city.
But last month UN Secretary General Ban Ki-moon said few countries were willing to send troops, as there was no peace to keep.
Somalia has not had an effective national government from 1991, since when various militias have been battling for control.