UPDATE 1-African Somalia force sees progress against rebels

* AU force takes undisclosed casualties in offensive
* Says rebels control three capital districts
* Beledhawo seized from rebels, more than 15 killed
(Recasts with AMISOM briefing)
By Mohamed Ahmed
MOGADISHU, March 5 (Reuters) - The African Union's peacekeeping force in Somalia (AMISOM) captured a key position from al Shabaab rebels in the capital, losing several troops in the fighting, its force commander said on Saturday.
Together with Somali government troops, the 8,000-strong AMISOM force started an offensive against the hardline insurgent group on Feb. 19 as a step towards returning the Horn of Africa country to stability after two decades of conflict.
Major General Nathan Mugisha said the force captured the former ministry of defence building in the north of the city, gaining control of a major al Shabaab base.
"By taking these positions we have effectively reduced their freedom of manoeuvre in that sector," Mugisha told a news conference in Nairobi.   Continued...