0635 GMT December 15, 2019
Nur Mohamed, a Mogadishu police officer, told Reuters the bomb had gone off at the heavily guarded Sayidka checkpoint.
Abdikadir Abdirahman, director of Amin ambulances, the city's sole rescue service, said three people had been killed, excluding the bomber, and one injured.
A Reuters photographer at the scene saw ruined cars and three-wheeled scooters overturned by the force of the blast.
The al-Qaeda-linked militant group al-Shabab claimed responsibility. Al- Shabab frequently carries out bombings and other attacks in Mogadishu in a campaign to topple Somalia's Western-backed federal government.
"We are behind the attack at the checkpoint from where the president's palace, parliament house and the interior ministry of the apostate government are guarded," said Abdiasis Abu Musab, the group's spokesman for military operations.
He said 13 government soldiers had been killed, without offering any evidence. The group usually claims a higher death toll from its attacks than that of the government.
At least 14 people were killed on Thursday when al-Shabab set off a bomb outside a busy Mogadishu hotel.