washington 400 u.s. marines artillery leave syria help capture city raqqa islamic state u.s.-led coalition fight militant group say thursday last month u.s.-backed militias declare victory raqqa islamic state former headquarter syria months fight help u.s.-led coalition city liberate isis run unit order home replacements call coalition say statement use acronym islamic state draw combat force make sense still continue efforts help syrian iraqi partner maintain security brigadier general jonathan braga director operations coalition say statement remain force continue work partner force defeat remain isis prevent re-emergence isis set condition international governments ngos help local citizens recover horrors isis short-lived rule say officially pentagon say 503 troop syria however last week u.s. officials say close 2,000 u.s. troop country late announcement would reduce number campaign islamic state wind unclear many u.s. troop remain syria special operations force work train advise local partner force include provide artillery support islamic state militants separately russia say already prepare withdraw military contingent syria russian news agencies report 400 u.s. troop leave syria coalition