As of September of last year, the CIA estimated that the Islamic State’s rapid acquisition of territory in Iraq and Syria was achieved by a force that numbered only 20,000 to 31,500 strong. Many of those fighters have likely been lost to attrition; due to death in combat or by coalition airstrike, surely ISIS forces have dwindled.
But those forces have been steadily augmented as a result of ISIS’s foreign recruitment efforts. A stream of foreign fighters from across the world have gravitated toward the nascent Islamist caliphate, and they are helping to swell ISIS’s ranks. According to one shocking report, foreign fighters are pouring into Syria at an “unprecedented’ pace. One U.S. intelligence official believes that approximately 20,000 foreign nationals from 90 countries have traveled to Syria to join the insurgency.
No precise numbers are available “but the trend lines are clear and concerning,” Nicholas Rasmussen, NCTC director, said in prepared remarks for a congressional hearing on Wednesday.
“The rate of foreign fighter travel to Syria is unprecedented. It exceeds the rate of travelers who went to Afghanistan and Pakistan, Iraq, Yemen, or Somalia at any point in the last 20 years,” he said.
The volunteers come from a range of backgrounds and “do not fit any one stereotype,” Rasmussen said.
“The battlefields in Iraq and Syria provide foreign fighters with combat experience, weapons and explosives training, and access to terrorist networks that may be planning attacks which target the West,” he said.
And that’s the key. Many of these fighters, 3,400 of whom are estimated to have traveled to Syria from Western nations, will be groomed to execute terrorist attacks inside the nations that make up the coalition targeting ISIS in Iraq and Syria.
So how large are ISIS’s forces? Estimates vary greatly, but one compelling bit of analysis via War on the Rocks parses a variety of estimates and examines the scale of the territory under ISIS control and the approximated number of soldiers required to hold that territory, and comes up with a reasonable guess:
In Iraq, that’s a population of 3,965,517 to 4,645,517 that ISIL has to control—about twice the size of the group’s Syria holdings. And these territorial holdings come on top of multiple ISIL contingents that maintain their own logistics and support personnel, and that are capable of carrying out battalion-sized offensive operations, including the al-Sarim al-Battar, al-Aqsa, Grozny, Sarajevo, Yarmuk, Jalut, Dawud, Jabal, Saiqa, Zilzal, al-Qa’qa, Hitin, and al-Qadisiyah battalions. (Note that “battalion” does not mean the same thing for ISIL as it does for U.S. forces: ISIL’s battalions are not as large.) With these factors in mind, Hisham al-Hashimi’s estimate of ISIL having 100,000 men under arms appears plausible. Further, if one takes into account ISIL’s establishment of multiple security bodies and the mass conscription it has imposed in Raqqa, Ninawa, and western Anbar, the overall Kurdish estimate of 200,000 men may be plausible as well.
“CENTCOM has said that it has killed 6,000 ISIL fighters in airstrikes alone since August,” the post via Daveed Gartenstein-Ross read. “If the low-end estimates are accurate, then between 20-30% of ISIL’s total manpower has been eliminated by airstrikes. Such a conclusion is clearly unrealistic.”
“Even if ISIL were able to replenish its ranks at a rate equal to the attrition, the group would be performing far worse on the battlefield if it had had to replace such a large percentage of its force in such a short period,” he continued. “By contrast, if you accept Hashimi’s figure of 100,000 ISIL fighters, the group has only lost about one-tenth of its total force.”
Whatever ISIS’s numbers are, it will be difficult to either “degrade” or “destroy” the Islamic State if it is continually augmented with foreign fighters.
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