The African Union is a continental union consisting of 55 member states located on the continent of Africa. The AU was announced in the Sirte Declaration in Sirte, Libya on 9 September 1999, calling for the establishment of the African Union.
Jihadists have attacked a military base where US soldiers train commandos in Somalia.
Local residents reported heavy blasts and gunfire at Baledogle airport in the southern Lower Shabelle region.
Military officials say the jihadists were repulsed without breaching The Perimeter fence.
No casualties were reported among the Somali military.
In a statement, for their "alertness and swift response".
"This attack Yet Again demonstrates al-Shabab violently opposes progress towards peace and prosperity in Somalia," he said.
Al-Shabab said in a statement it had launched the raid, adding: "After breaching the perimeters of the heavily fortified base, the mujahideen [holy warriors] stormed the military complex, engaging The Crusaders in an intense firefight. "
The Base , about 100km (60 Miles ) west of the capital Mogadishu, is said to house US Special Forces , Somali Special Forces and Ugandan peacekeepers. It is used as a launch site for US drones as well as being a training centre.US Somali operation shrouded in secrecy
By Mary Harper, BBC World Service Africa editor
The fact that al-Shabab managed to attack two foreign targets in a single day proves its enduring power, 13 years after it came into existence. It shows it is a well-coordinated force, with a sophisticated intelligence network.
The Group does far More Than stage attacks on its enemies. It imposes fines and taxes, even in government-controlled areas. It provides effective - if brutal - judicial services, which are as popular with those living outside the areas it controls as those inside them.
It is essentially a governing force, and is likely to remain so until the Somali government and its allies form a credible, functioning alternative.
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Separately, an Italian military convoy was hit by an explosion in Mogadishu itself, Italy's defence ministry said. No casualties have as yet been reported in this attack.