ISIS has reportedly been manufacturing arms on a massive scale in Iraq.

FOX's Jessica Golloher has the details from the Middle East Bureau:

ISIS maintained a robust and reliable supply chain between Iraq and Turkey that allowed the insurgents to produce tens of thousands of weapons. This according to a new report by London-based Conflict Armaments Research.

The group found that as an offensive by Iraqi forces to retake Mosul continues, the extremists are losing the capacity to manufacture weapons on such a large industrial scale.

Executive director James Bevan tells the Associated Press that ISIS' highest trained bomb makers have most likely already fled into Syria and Southern Turkey. The offensive to retake Mosul from ISIS began in October.

In the Mideast bureau, Jessica Golloher, FOX News.