sentences:  Throughout 2007 and 2008, Al-Shabaab scored military victories, seizing control of key towns and ports in both central and southern Somalia.At the end of 2008, the group had captured Baidoa but not Mogadishu.By January 2009, Al-Shabaab and other militias had managed to force the Ethiopian troops to retreat, leaving behind an under-equipped African Union peacekeeping force to assist the Transitional Federal Government's troops.