“We continue to believe the number of Americans who have aimed to join the fight either going into Iraq and Syria, or trying to and being stopped in that effort, is in the neighborhood of a 180,” Rhodes said.
US intelligence estimates the number of foreign fighters in the Islamic State is between 20,000 and 30,000. The militant group also recruits or coerces fighters from areas under its control in Iraq and Syria.
Earnest noted that in comparison, the number of foreign fighters joining the Islamic State from Europe “is a source of grave concern for our European partners.”
“In terms of our own security, we are very focused on the foreign fighter issue because, ultimately, that could provide a pipeline for people to return to the United States, Europe or other countries to potentially carry out attacks,” Rhodes added.
Countries that are leading sources of fighters for the Islamic State are Saudi Arabia, Tunisia, Jordan, Libya, Morocco, but also several countries in Europe including Britain and France, according to media reports.
