beirut syrian iraqi force close last scrap islamic state caliphate straddle remote border area two countries already witness jihadists likely response comrades mount last stand syrian capital raqqa city hawija iraq militants seize syrian town al-qaryatayn launch big attack months ramadi late last month kind guerrilla insurgency countries foresee turn expect daesh terrorist organization capacity fight field finish remnants resort type guerrilla operation certain period time forever say syrian military source use arabic acronym islamic state continue ability mount attack areas think eliminate hind efforts stabilize regions fight wan iraq islamic state originate prove record fall back upon local network rise anew condition allow far show capacity syria might find challenge iraq sectarian divisions thrive less pronounce syria face competition jihadist loyalty powerful militant group daesh essence iraqi organization survive extent iraq syrian members dissolve syrian salafi jihadist group say hisham hashami adviser islamic state iraqi government countries show exploit hole leave overstretch enemies carry spectacular attack one syria al-qaryatayn clearly spread panic tie oppose force also prove able carry bomb assassinations areas control iraqi syrian governments u.s.-backed kurdish militias rival jihadist rebel group signal ability survive underground jihadist syrian rebel faction oppose islamic state say group enough support among young men give latent capacity revive believe possible give ideology spread widely among youths something new emerge jihadist say point highly effective propaganda machine deploy islamic state last three years al-qaryatayn attack begin even 29 september 250 militants gun rocket mortar spread around area terrible speed say ayman al-fayadh resident particularly alarm government declare al-qaryatayn safe months ago help residents move back home jihadists finally force three weeks fight around outskirts al-qaryatayn take revenge slaughter score inhabitants bloodthirsty spare anyone fayadh say syrian military source say take three weeks retake town inhabit army try avoid civilian casualties however attack show towns syria desert arm force spread thinly vulnerable islamic state operations tie oppose armies people afraid daesh return say syrian journalist visit town week kill anyone take part pro-government protest body throw streets well fayadh also say townspeople among attackers indicate islamic state use years rule build local support network establish sleeper cells future attack something could replicate elsewhere syria go continue look place plan finance resource launch attack say colonel ryan dillon spokesman u.s.-led coalition note islamic state often use sparsely populate areas assault ramadi take place three days militants attack iraqi security force suicide car bomb mortar machine gun city apparently lose months early big challenge iraq syria co-opt sunni arab tribes risk revival jihadist insurgency suuni-shi ite divide plague iraq since u.s.-led invasion 2003 ignite civil war shi ite party back iran dominate government use militia force mostly sunni insurgents syrian government may problem ally region main shi ite power iran militia group lebanon hezbollah lead president bashar al-assad shi ite offshoot sect also challenge u.s.-backed syrian democratic force sdf alliance northern syria spearhead kurdish group sometimes struggle convince arabs protect interest depend degree fight assad sdf incorporate settle tribes govern structure say andrew tabler fellow washington institute near east policy even northwestern syria rebel group include jihadist factions hold sway hardship insurgent infighting might create space islamic state seize grind beside al-qaryatayn attack group islamic state fighters manage take pocket territory rebel-held areas near hama recent weeks battle rival jihadist group control several villages use bomb attack assassinations target government-held cities west kurdish security force northeast islamist rebel factions northwest isolate enclave hold yarmouk camp south damascus also show renew aggression take headquarter neighbor rebel group month force jihadist rebel say believe islamic state could repeat strategy use iraq last decade retrench attack rebound virulent form period weakness islamic state depend ideology spread jihadist say appear experience repeat could carry bomb guerrilla war islamic state guerrilla attack point future strategy