beirut syrian warplanes take air base hit u.s. cruise missiles friday carry air strike rebel-held areas eastern homs countryside syrian observatory human right say u.s. navy fire dozens missiles air base near homs city response chemical attack week washington ally blame damascus government british-based observatory group monitor syrian war use source grind say eight people kill u.s. attack extent damage shayrat air base entirely clear syrian warplanes do impossible order continue use sorties observatory tell reuters syrian jet take air base u.s. missiles strike syrian observatory