For the first time, US spy chiefs have revealed an official estimate of 7,000 foreign Islamist fighters from 50 countries on the ground in Syria, saying they are mostly from Europe and the Middle East.
Estimates on foreign fighters by nation have varied widely, but of particular concern are many hundreds of fighters from EU member nations, who after the war will retain al-Qaeda contacts and EU passports that will give them access to virtually everywhere in the world.
With the Syrian Civil war dragging on longer than anyone had figured, the foreign fighters have stayed in Syria for the long haul, and more and more of them keep showing up, leading al-Qaeda and others to build training bases just for foreign brigades.
But when the war finally does end, those fighters will scatter around the world, using the training and indoctrination they are getting in Syria to launch strikes everywhere.