Casualties are reported after a suicide bomber in Somalia attacked a military base housing African Union soldiers and Somali security forces.

Somali officials say a car laden with explosives blew up Saturday outside the military base in the town of Afgoye, about 30 kilometers west of the capital, Mogadishu.

Officials are investigating further details of the incident, including the number of casualties.

Last month, Somali forces backed by African Union troops pushed al-Shabab militants out of one of their strongholds — the Afgoye corridor. The corridor includes sprawling camps for about 400,000 internally displaced Somalis.

At the time, military officials said al-Shabab was preventing aid groups from operating in the area.

Al-Shabab, an al-Qaida-allied group, is fighting to overthrow Somalia's transitional government and impose a strict form of Islamic law.