In a statement hours after a car rigged with explosives went off at a military checkpoint near the city’s main national theatre killing five people, a website supporting the group warned residents of the capital that Shabaab would strike again.
The latest bombing comes a week after a Shabaab kamikaze rammed his rigged vehicle into a building in downtown Mogadishu.
Although the militants have been driven from much of Somalia including from the capital since 2011, the group still retains a capability to strike Mogadishu with devastating effects.
Shabaab has been trying to overthrow the Somali government and replace it with a puritanical brand of religious authority.
It has also launched deadly bombings in neighbouring Kenya for contributing troops to an African Union peacekeeping force in Somalia.