The blast took place in Sinka Dher area of the region, where the bomber who was sitting inside a car blew up himself.
Anadolu Agency quoted Somali police as saying that the suicide attack targeted a security checkpoint.
"The blast was a suicide car bomb blast and was hit in our security checkpoint in Sinka Dher, three people including the attacker were killed, and three civilians were also wounded" police officer Mohamed Bulle said.
"Our security forces prevented the suicide attacker from entering the city which we believe that was its main target" he added.
The militant group al-Shabaab claimed responsibility for the attack.
However, spokesman for the internal security minister, Abdi Asis Ali Ibrahim, has denied al-Shabaab's claim.
This attack comes after a twin suicide car bomb blasts that ripped through the Somali capital on Friday and killed around 45 people. (ANI)