article_snippet: More than 20,000 foreigners have gone to fight for ISIS, the terror group that controls portions of Iraq and Syria, experts have told Congress.
article_snippet: National Intelligence Director James Clapper said 180 Americans have tried to go to fight in Syria.
article_snippet: It's unclear how many of those were attempting to join ISIS.
article_snippet: Some 100 other Americans are believed to have either fought in Syria since 2011 or been arrested before Some 100 other Americans could get there, according to Peter Bergen, CNN's national security analyst.
article_snippet: Former jihadist Mubin Shaikh said many of those who are attracted to ISIS or other militant causes are struggling to combine those who are attracted to ISIS or other militant
highlights_snippet: Growing numbers of Americans are attracted to ISIS .
  
highlights_snippet: More than 20,000 foreigners have gone to fight for ISIS, experts have told Congress .