Lt. Col. Paddy Ankunda says the gunmen tried to enter the base on Saturday but were stopped by AU troops. He says the gunfight was still going on and casualties were unclear.

Resident Mohammed Abdi says he heard several large explosions near the base but it was not clear what caused them.

About 9,000 AU troops are in Somalia supporting the weak UN-backed government against Al-Qaeda linked Al-Shabab insurgents. The AU and government control almost all of the capital but the insurgents still launch daily attacks.