“The scale of this recent mobilization is unprecedented,” says the report. “In May 2015, the United Nations Security Council estimated more than 25,000 foreign fighters from more than 100 countries have joined ISIS and other jihadist groups in Syria. Even though precise data is virtually impossible to obtain, it is believed that some 5,000 European citizens or residents have become foreign fighters in Syria and Iraq, a number that dwarfs all previous mobilizations (Afghanistan, Bosnia, Chechnya, Iraq, Somalia, and Mali) combined. Particularly alarming are numbers from certain countries, such as the 1,200 estimated to have left France, and the 400 who left Belgium, a country of only 11 million.”
The report found that “the numbers in the US, while similarly difficult to measure precisely, are significantly lower than those in most European countries.” In June 2015 the FBI stated that “upwards of 200 Americans have traveled or attempted to travel to Syria to participate in the conflict.” A few weeks later, the Office of the Director of National Intelligence estimated that more than 250 individuals from the US had traveled or attempted to travel to the conflict area, a few dozen had joined the ranks of ISIS, and some 20 had died. But in October 2015, Comey revealed that the FBI had a staggering 900 active investigations against homegrown violent extremists.
The report confirms that “publicly available information confirms a sharp surge of jihadist activities in the US, especially when compared to dynamics seen in the years since the wave of arrests following 9/11. Since March 2014, 71 individuals in one way or another linked to ISIS have been charged in the US for terrorism-related activities. The number of arrests has spiked in recent months, with 56 arrested since January 2015. In the same period, a handful of attacks have occurred across the country.”