The U.S.-led military coalition is gaining valuable insight into how the Islamic State in Iraq and Syria (ISIS) is employing foreign fighters as local Syrian forces close in on one of the terrorist group's strategic hubs in Manbij, Syria.
As those forces cover more ground in Manbij, they have collected more than 10,000 items left behind by ISIS that provide insight on how it is receiving, training, using and dispatching foreign fighters.
Those items include "thumb drives, text books, notebooks, all sorts of materials," Operation Inherent Resolve spokesman Army Col. Chris Garver said at a press briefing on Wednesday.
"They've gotten more than four terabytes of digital information off the battlefield as well — laptops, that sort of thing," he said.
The information haul could provide insight to ISIS's plotting of attacks outside Iraq and Syria, Garver said.
"Anything that can connect us to external operations from Syria is a benefit to everybody. It benefits the whole global coalition that is working to counter ISIL's operations around the world," he said, using another acronym for ISIS.
The coalition has learned so far that ISIS had established three centers to receive foreign fighters in Manbij, a northern Syrian city along the border with Turkey, from where many foreign fighters are flowing into Syria.
Last week, French intelligence sources told the news source Le Figaro that about 100 foreign fighters per week were still coming through the border.
"As a foreign fighter would enter, they would screen them, figure out what languages they speak, assign them a job and — and then send them down into wherever they were going to go, be it into Syria or Iraq, somewhere," Garver said.
Garver said local Syrian forces backed by coalition airpower have retaken about half of the city but said it would take some time to capture the city from ISIS.
"We've seen a more concentrated effort [to] rig houses as house-borne IEDs [improvised explosive devices]. ... Luckily, a lot of those have not gone off," Garver said.
"The enemy is fighting very hard. They're putting snipers in minarets, in mosques. They've got machine guns. They've got IEDs all over the place."