An Islamist faction waging war in southern Somalia has appointed a new administration for Lower Shabelle region, Radio Garowe reported Saturday.

Muktar Robow "Abu Mansur," the Al Shabaab spokesman, was present in the provincial capital Marka where Sheikh Abdirahman "Siro" Ahmed was appointed as the new governor.

"We call on aid groups to continue their humanitarian efforts and we promise full cooperation," Abu Mansur said at the ceremony.

Sheikh Abdirahman Siro, the new governor of Lower Shabelle, vowed to rule the region with justice and to use Islamic law as the basis of all legislation.

The Islamist governor will be assisted by an executive team of officials in charge of security, the courts, education and finance, according to Al Shabaab officials.

Lower Shabelle is a region that borders Mogadishu, the Somali capital. The unarmed natives of Lower Shabelle have suffered disproportionately under the brutal rule of warlords from non-native armed clans since the collapse of the Somali government in 1991.

The region has a number of port and airport facilities that play an important role in the delivery of humanitarian aid to hundreds of thousands of Somalis, many of them fleeing the insurgency in Mogadishu.

Many locals have welcomed the Al Shabaab takeover because the Islamists restore law and order in regions under their control, while warlords can only thrive in disorder.

Al Shabaab, a faction of the Islamic Courts Union, is considered a terrorist organization by the U.S. government.