Mogadishu , Somalia ( CNN ) -- A Somali lawmaker was killed and another was injured when a bomb hidden in their car exploded while they were headed to a conference on security , officials said . Parliamentarian Isack Mohamed Ali , popularly known as Isack Rino , was killed , and lawmaker Mohamud Abdi-dhuuh was seriously injured , said Mohamed Abdiqadir Mohamed , district commissioner of Mogadishu 's Hamarweyne district . Four passersby were also hurt . The parliamentarians were on their way to a national conference on security when the bomb , hidden under one of the car 's seats , exploded . The Islamist rebel group Al-Shabaab claimed responsibility for Monday 's bombing in a statement posted to a pro-militant website . Prime Minister Abdiweli Sheikh Ahmed said those behind the `` cowardly '' attack would be found . `` Somalia has today lost a committed parliamentarian who worked tirelessly to serve the people of Somalia and help rebuild our country , '' Ahmed said in a statement . `` This cowardly attack will not derail the progress made in Mogadishu and across Somalia . The security agencies will investigate this cowardly killing and ensure that those who carried out this attack face justice . '' Journalist Omar Nor reported from Mogadishu ; CNN 's Holly Yan wrote from Atlanta . Tara Kangarlou also contributed to this report .
One parliamentarian was killed and another was seriously injured . The lawmakers were on their way to a national conference on security . Al-Shabaab claims responsibility for the attack .