Nine people including a senior local government official were killed on Wednesday in a suicide bombing in southern Somalia claimed by the Al-Shabaab jihadist group, police and witnesses said.

The attack occurred outside the administrative office in the town of Marka, where the district commissoner Abdullahi Ali Ahmed Wafow was speaking with local people, police said.

"Commissioner Abdullahi Wafow was killed in an explosion together with eight other people, most of them security personnel," a police officer in Marka, Ibrahim Ali, told AFP by phone.

"The police are still investigating the incident but there are already indications that a suicide bomber carried out the deadly attack."

Al-Shaabab claimed responsibility in a brief statement, saying the "martydom operation" had targeted the commissioner.

"The bomber ran up to the commissioner and blew himself up," witness Abdukadir Hassan said.

"I was close to where the incident occurred, the scene was horrible with these shattered pieces of human flesh all around." 

Somalia's new President Hassan Sheikh Mohamud said this month that ending Al-Shabaab's insurgency required more than a military approach, but that his government would negotiate with the group only when the time is right.

The jihadists have been seeking to overthrow the fragile foreign-backed government in Mogadishu for about 15 years.

Its fighters were driven out of the capital in 2011 by an African Union force but the group still controls swathes of countryside and has the capacity to wage deadly strikes on civilian and military targets.

Last week, Al-Shabaab launched a rare incursion into neighbouring Ethiopia, with regional authorities there saying they had killed about 100 militants.