Al-Shabab says it carried out attack near a detention centre, the latest in a series of explosions to strike Mogadishu.
A ceasefire between forces of two semi-autonomous regions of Somalia broke down as fighting over a disputed border area killed at least 20 people.
Fighters from Galmudug and Puntland clashed on Sunday in the town of Galkayo, which straddles their common border and is divided under the control of rival clan militias, a week after the truce was reached.
Under terms of a ceasefire deal mediated by the United Arab Emirates – and which was welcomed by the two sides and Somalia’s federal president – forces of both regions were supposed to be withdrawn from the disputed area this past week.
The deal also called for those who had fled Galkayo because of previous fighting to be allowed to return.
“We were shocked to see Puntland forces inside Galkayo south and pounding us with shells and bullets,” Hirsi Yusuf Barre, mayor of Galkayo south, which is controlled by militias loyal to Galmudug, told Reuters news agency.
“We lost seven soldiers and 20 others were wounded. We also lost a car. We repulsed them and now Galkayo is calm,” he added
Each region’s authorities blamed the other for starting the fighting.
“Galmudug does not want peace. We shall continue fighting till we cleanse Galmudug forces,” said Colonel Mohamed Aden.
Aden said their side had lost 12 soldiers and 20 others were wounded. They also captured two vehicles and four prisoners.
“We also took some land in the outskirts of Galkayo,” he said.
Mahad Ali Mohamed, a reporter for Codkamudug, a Galmudug radio station, was also killed in the crossfire, said Hanad Abdi Farah, the station’s manager.
“Bullets hit him in the head, it was in the morning and he was from home and heading to the radio station,” Farah said, adding Mohamed was rushed to the hospital but died of his wounds.
As violence between these groups began to escalate a month ago, schools in Galkayo were forced to close and some people fled the town.
Somalia has been gripped by conflict since the downfall of dictator Mohamed Siad Barre in the early 1990s, and the armed group al-Shabab has been one of the main causes of unrest in the past two decades.