The mayor of a Somali town and his three bodyguards were killed Monday by a bomb placed on a road, a local official said.

The bomb was set off by remote control as Afgoye mayor Ali Addow Ali's car was approaching, said Abdulkadir Mohamed Nur Siidii, governor of the Lower Shabelle region where the incident took place.

"Three civilians who were passing by the road were wounded," Siidii added.

Sheikh Abdiaziz Abu Muscab, a spokesman for the radical Islamist group al-Shabaab, told pro-insurgent radio Andalus that the group had carried out the attack.