Mortar shells fired into homes in the Somali capital of Mogadishu has killed three people and wounded five, police and ambulance services said on Friday, a day after the government changed heads of security agencies.

Police said they suspected al Qaeda-linked al Shabaab were behind the attack, in which mortar rounds landed on homes in Wadajir district, in the vicinity of Mogadishu airport.

"We have carried three dead women and five others injured, including a woman and children. Mortars landed on their home today," Abdikadir Abdirahman, the director of Amin ambulance services, told Reuters on Friday. "Mortars believed to be fired by al Shabaab killed three people of the same family and injured several others. We are still investigating where they were fired from," Osman Mohamed, a police officer, told Reuters on Friday.

Al Shabaab were not immediately reachable for comment. In the past, the group, which aims to impose its own harsh version of Islam in Somalia, has taken responsibility for blasts and gun attacks in the capital and elsewhere in Somalia.

On Thursday, President Mohamed Abdullahi Mohamed, replaced his security chiefs and called on al Shabaab fighters to surrender within 60 days in return for education and jobs.

Al Shabaab is carrying out increasingly deadly bombings despite losing most of its territory to a 22,000-strong African Union peacekeepers supporting the Somali government.