nairobi/mogadishu size methods late truck bomb mogadishu show international somali government efforts stop kill fail partly intelligence gather counter attack disjoint security source say 300 people kill bomb heart capital saturday deadly attack history horn africa nation islamist insurgency al shabaab blame blast happen car bomb truck bomb head airport detonate prematurely somali security service donor nations work blame disorganization divisions suppose work detect stop attack say hussein moalim mohamud sheikh ali former national security adviser president national security architecture tatters tell reuters shabaab attack symptom great political dysfunction state increase frequency grow size attack threaten fragile security gain make somalia ahead withdrawal african union peacekeepers end year also concern countries region al shabaab active kenya uganda 2016 723 people die 395 attack somalia 46 dead 36 attack 2010 accord confidential report produce early year nairobi-based thinktank sahan research initial swab test site attack show trace potassium nitrate fertilizer component indicate al shabaab manufacture explosives well buy harvest munition experts say compete program fund different donor nations lack centralize database hurt efforts analyze intelligence relate improvise explosive devices ieds four western one somali security source tell reuters letter somalia minister internal security address unite state britain unite nations may complain competition secrecy among agencies gather intelligence multiple actors involve mean process highly disorganize ... cause severe problem governmental counter-terrorism efforts say letter see reuters pressure build president mohamed abdullahi mohamed must ensure somalia fledgling security force ready step 22,000-strong au force leave government already stall release report joint u.s.-somali raid bariire august residents say kill 10 civilians political disagreements threaten co-operation somalia federal regional force last week minister defense army chief resign without give reason interior ministry spokesman resign week somali police respond request comment high-grade explosives obtain high-grade military explosives material make bomb explode involve harvest capture munition buy someone else make explosive allow insurgents build big bomb accord sahan report upcoming report u.n. panel experts monitor arm embargo somalia accord u.n. report due publish next month u.s. terrorist explosive device analytical center fund federal bureau investigation confirm presence potassium nitrate six major vehicle-borne bomb incidents since 2016. potential use hme home-made explosive al shabaab would allow group rely less process harvest explosives munition slow laborious allow ing militant group increase frequency explosive weight ieds say report al shabaab want overthrow somalia u.n.-backed government impose strict islamic law yet claim responsibility saturday attack keep previous incidents large number civilians kill mass civilian deaths cause deep divisions among fighters security source knowledge discussions within group say former top al shabaab commander mukhtar robow abu mansur condemn attack photograph local media donate blood robow defect government august u.s. government remove million bounty capture two mogadishu-based security source outline events lead late attack reuters say car bomb truck bomb deploy hit mogadishu international airport warren build ring barb wire blast wall house contractors diplomats european union military train mission one bomb would breach checkpoint open way large bomb one western security contractors tell reuters also fighters nearby ready come inside base driver car bomb drive checkpoints week ahead attack pay small bribe get security force use presence say large truck enter city pass one checkpoint stop one know kilometer five panic try force way get snarl traffic next fuel truck could see truck speed also hear gunshots behind police must chase say mohamed ali 21 injure blast advance come many cars street truck driver swerve abruptly leave lane tyres get stick highway divider follow blast smoke fireball tear intersection incinerate hundreds civilians many badly burn identify bury mass grave driver car bomb detain another checkpoint soldier take question bomb also detonate three security source tell reuters identify al shabaab deadly somalia blast reveal flaw intelligence efforts