mogadishu suicide bomber disguise policeman blow inside police train camp somalia capital mogadishu thursday kill least 18 officer officials say police spokesman major mohamed hussein say attacker strap explosives body infiltrate general kahiye police train academy early morning parade police prepare 74th anniversary police day want start exercise suicide bomber come blow lose 18 police officer 15 others injure muktar hussein afrah somalia deputy police commander tell reporters blast scene police always continue work despite death police early put death toll 15. reuters witness attempt visit site blast say police seal hours late allow witness saw body part suspect bomber grind field police officer train witness say grind nearby also wash remove blood stain people bury body police academy militant islamist group al shabaab claim responsibility attack give high death toll kill 27 police officer injure abdiasis abu musab group military operations spokesman tell reuters al shabaab carry frequent bomb mogadishu towns group ally al qaeda wag insurgency u.n.-backed government african union ally bid topple weak administration impose strict interpretation islam militants drive mogadishu 2011 since steadily lose territory combine force african union peacekeepers somali security force tuesday u.s. africom say u.s. military conduct air strike vehicle say strap explosives 65 km southwest mogadishu thursday attack come time african union finalize plan trim peacekeeping mission call amisom 22,000-strong au force schedule leave 2020 security experts say al shabaab could find easy stage attack peacekeeping force reduce government force find hard replicate work time somalia could become safe militants link al qaeda currently yemen experts say peacekeepers deploy help secure government struggle establish central control country plunge civil war early 1990s suicide bomber kill least 18 police academy somalia 's capital