aboard air force one u.s. president barack obama convene meet national security council next week central intelligence agency headquarter review fight islamic state militants white house say friday meet hold wednesday come administration weigh plan increase number u.s. special operations force deploy syria try advance recent gain islamic state top u.s. general joseph dunford chairman joint chiefs staff say work options present obama increase u.s. force iraq bolster iraqi force prepare major offensive militant group mosul obama hold similar meet pentagon state department fight islamic state hold areas syria iraq particular operational reason white house spokeswoman jen friedman tell reporters next series meet obama discuss islamic state cia next week