At least 13 people were killed when two vehicles packed with explosives went off as they were driven towards a base for African Union troops in the Somali capital, according to officials and witnesses.
Local journalists said the blasts had been caused by two bombs. At least one was detonated by a suicide attacker in a vehicle near a checkpoint, they said.
There are reports of casualties among security guards on the checkpoint.
The militant Islamist group, al-Shabab, which is allied to al-Qaeda, has carried out frequent attacks in Somalia, including in Mogadishu, in an attempt to oust the UN-backed government.
The group has been pushed out of most of the main towns it once controlled, but analysts say it remains a potent threat.
It has been increasing its attacks ahead of planned elections in Somalia.
This is a developing story, more details awaiting.
(With Agency Inputs)