The number of Westerners who have joined ISIS in Syria and Iraq continues to grow, according to U.S. officials, and now stands at 3,400. Those officials hope recent military successes against ISIS will help stem the flow of fighters. Gen. James Clapper, the director of national intelligence, told Congress Thursday ISIS now has 20,000 foreign fighters, up from 16,000 last fall, out of a total fighting force of as many as 31,000. Clapper's testimony also upped the number of U.S. citizens who've traveled or attempted to travel to Syria. Six months ago, the number was estimated at 100, then more recently 150. On Thursday, Clapper put the number at roughly 180.
