The U.S. and its allies have dropped a torrent of missiles on Iraq and Syria in an attempt to stamp out militant group ISIS.
But the recent airstrike on a group referred to as "Khorasan" in an area west of Aleppo is a sharp reminder that ISIS is not the only — or even the most dangerous — terrorist threat in the region.
According to analysts, Khorasan is believed to be an elite, militant al-Qaeda cell made up of seasoned fighters from Afghanistan, Pakistan and Yemen who were dispatched by the core leadership to form a base of operations in Syria.
Experts say the name, used by the U.S., might also be used by jihadists outside the region, even though the fighters do not call themselves Khorasan.
In a piece for the web site The Intercept, investigative journalists Glenn Greenwald and Murtaza Hussain question the existence of Khorasan, calling it "the wholesale concoction of a brand new terror threat."