( CNN ) -- A suicide bomber hit an African Union Mission in Somalia convoy on Monday , killing 16 people , Lower Shabelle Gov . Adukadir Mohamed Sidi said . Sidi said the explosion destroyed two buses traveling behind the military convoy , which was transporting the governor as he traveled back from Mogadishu . The blast killed 16 civilians and injured 22 people , including two soldiers , he said . The Al-Shabaab terrorist group claimed responsibility for the attack and said Americans and South Africans were among those killed . The bombing comes a week after a U.S. airstrike claimed the life of the group 's leader , Ahmed Godane . The group appointed a new leader last week and said Godane 's death would not stop its attacks . Somalia has been on high alert for strikes since . Al-Shabaab names successor to slain leader ; Somalia on alert . CNN 's Faith Karimi , Jason Hanna and Michael Pearson contributed to this report .
16 killed in Somalia suicide bombing targeting governor 's convoy . Two African Union Mission in Somalia troops are wounded , he said . Al-Shabaab claims responsibility for attack .