From the outside, the Islamic State terror group’s self-declared caliphate appears to be unraveling, its cities lost and its fighters fleeing.
There is growing concern, however, that what seems to be a fraying proto-state is actually an enemy force that is fanning out, sacrificing territory and battles now so it can wreak havoc on its home turf in years to come.
The warning signs for the strategic shift by IS have been visible for months, showing up in the way its fighters have retreated from former strongholds and in the way it appears to be setting up its defense of Mosul, the group’s capital in Iraq.
While IS fighters there are expected to battle to the very end, the group’s best and most effective forces most likely will not be among them.
“Many of the top commanders have already left,” David Witty, a retired U.S. Army Special Forces colonel and former adviser to the Iraqi Counter Terrorism Service told VOA.
More could soon follow.
“In previous battles, large numbers of IS fighters have not been captured,” Witty said. “They will be ready to escape with somewhere around 50 percent of their strength.”
Atheel Alnujaifi, a former governor of Nineveh province who now heads Iraq’s National Mobilization Front and its approximately 4,000 fighters, believes the strategic retreat is well underway.
“The information coming from inside Mosul says that most of the foreign fighters are leaving,” Alnujaifi said during an interview last month. “I don’t think that more fighters will come.”
U.S. military officials admit the number of fighters left to protect Mosul, a force once thought to be possibly 12,000-strong, may have been reduced by half.
“Somewhere between 5,000 or so fighters are inside Mosul,” former Operation Inherent Resolve spokesman Colonel Chris Garver told Pentagon reporters earlier this month.
Other analysts argue that the number of IS fighters in and around Mosul is higher.
Growing IS trend
Still, there is growing concern that the overall trend is part of an IS strategy to melt into the background.
“They’ve had a very long time to ensure their support zones are intact, and they are deeply entrenched,” warned Patrick Martin, Iraq research analyst with the Institute for the Study of War.
Already, IS has seen success in reigniting its insurgent capabilities in areas it has lost to other military forces.
One such example is Iraq’s Diyala province, initially cleared of IS in early 2015. But since then, the number of IS terror attacks has steadily increased, forcing Iraqi security to start all over again.
“The long game is that ISIS is intent on keeping some of these attack-and-support capabilities in recaptured areas without necessarily the intent of controlling terrain,” Martin said, using an acronym for the terror group.
U.S. officials also worry IS will escape through black market and criminal networks that have already profited from the terror group’s exploits.
“Smuggling networks have been key to their ability to get material in and out of their territory,” Acting Under Secretary for Terrorism and Financial Intelligence Adam Szubin told the August issue of the CTC Sentinel.
“You’re talking about smuggling routes that have existed for centuries, in many cases millennia,” he said. “These middlemen are civilians, and they are not going to be who the military is looking for in terms of striking against ISIL.”
There are also expectations that some IS fighters will try to hide among the civilian Sunni population escaping the conflict into camps and towns around Iraq and Syria.
"After significant coalition operations to liberate cities, ISIS fighters often flee in convoys intermixed with civilians,” said Nicholas A. Glavin, a senior researcher at the U.S. Naval War College’s Center in Irregular Warfare and Armed Groups.
He said the tactic, whether deliberate or coincidental, prevents coalition airstrikes from eliminating IS fighters as they flee.
Once intermingled with the civilian population, it can be nearly impossible to root them out, as IS’s predecessor, al-Qaida in Iraq, showed from 2003 to 2011. Even with thousands of U.S. troops on the ground, there were neighborhoods that were never actually cleared of al-Qaida militants.
Now, it may be even more difficult.
“ISF [Iraqi Security Forces] are not good at isolating urban areas,” said Witty, the retired Army Special Forces colonel. “The option to escape will always be there.”
And once IS fighters have escaped, officials fear the loose but resilient support networks will enable them to lie dormant and undetected until an opportunity presents itself.
“It’s very difficult to root them out in one sweep,” said Martin of the Institute for the Study of War.