ERBIL, Iraq –  As the battle for its Iraqi stronghold of Mosul looms, an increasingly desperate ISIS has replaced much of its depleted senior ranks with child soldiers and drugged foreign fighters ill-equipped to use what’s left of the terrorist army’s stolen armaments, according to both Kurdish and national intelligence sources.

Since ISIS captured Iraq’s second-largest city in June 2014, near daily skirmishes with Kurds and Iraqi national forces, as well as coalition air attacks, have taken a heavy toll on the battle-hardened former military officers who formed the terrorist army’s backbone. The attacks, as well as the 20-month isolation of Mosul, also have left ISIS weaponry destroyed or degraded, say experts.

“In the beginning they had powerful weapons they stole from the Iraqi Army, but over time the coalition strikes have destroyed such weapons,” Jaffar Ibrahim Eminki, deputy speaker of the Kurdistan Parliament, told FoxNews.com. “And ISIS is being defeated at many strategic points.”

Baghdad has said the fight to retake Mosul will happen this year, although U.S. Marine Lt. Gen. Vincent Stewart, director of the Defense Intelligence Agency, told the Senate Armed Services Committee the city will not be recaptured in 2016.

“Securing or taking Mosul is an extensive operation and not something I see in the next year or so,” Stewart said, while not discounting the possibility the effort could begin much sooner.

While Kurdish and Iraqi forces prepare to attack, with U.S. forces on hand to train them, each day that passes weakens ISIS forces holed up in and around the city, said Kamal Kirkuki, spokesman for the Kurdistan Democratic Party. The main reason, he said, is that the former Saddam Hussein Sunni loyalists — who turned to ISIS when the nation’s Shia majority took over — are dwindling.

“At the beginning, the Da’esh was all former Iraq military and Baath party leaders. They had experience, top bomb tech specialists and most were very skilled,” Kirkuki said, explaining many of those original professionals have since died in the battle. “The new ones who have contacted them online and come to join have much less experience.”

ISIS in Iraq is propping up its fighting ranks by bringing in more “reserve fighters” – many as young as 13 – but who have little or no combat experience, according to Kurdish military leaders who clash frequently with the terrorist army on the frontlines around Kirkuk.

An example of ISIS’ lack of battlefield know-how came in a recent battle in northwest Kirkuk, according to Kirkuki. Leaders from the Kurdish Peshmerga forces reported that ISIS had planted scores of IEDs between the two opposing frontlines, prompting the Peshmerga soldiers to circle around and attack from behind.

“They were waiting for us face-to-face and they didn’t think of that option, something so simple,” Kirkuki said. “ISIS is really stupid. If they weren’t stupid they wouldn’t join ISIS.”

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