About 20 thousand foreigners from 90 countries make up the ranks of the terrorist group operating in territories of Syria and Iraq, known as the Islamic State (IS), three thousand 400 of them from Western countries.
The news became known on Wednesday in this capital, citing US intelligence sources, which estimate that about 150 Americans tried to reach the Syrian-Iraqi conflict area.
Some of them were arrested on the way, others died in the area and a smaller group is in combat, say these sources.
In its view, Washington fears that some of the rebels linked to IS might return undetected to their home countries in Europe or America, and cause terrorist actions.
Intelligence officials also acknowledged that it has been difficult to trace the Americans and Europeans that entered Syria to join the ranks of the IS.
Meanwhile, the head of the National Counterterrorism Center, Nick Rasmussen, assured that the number of foreign fighters traveling to Syria is unprecedented, far exceeding the number of foreigners who joined the jihad in Afghanistan, Pakistan, Iraq, Yemen, Somalia, or anywhere in the world over the past 20 years. (PL)