mogadishu unite state military carry air strike somalia al shabaab al qaeda-linked islamist insurgency want topple u.n.-backed government u.s. africa command say wednesday say several militants kill strike 60 miles northwest capital mogadishu tuesday 1500 gmt coordinate somali government africom say statement al shabaab publicly commit plan conduct attack u.s. partner region africom say early month u.s. warn threat diplomatic staff mogadishu direct non-essential staff leave capital al shabaab push mogadishu 2011 lose control somalia cities towns group retain strong presence south center still carry major attack blame bomb mogadishu last month kill 350 people group aim topple somalia government drive african union peacekeeping troop impose harsh interpretation islamic law u.s. mount air strike al shabaab militants somalia