BEIRUT, Lebanon -- As Iraqi forces tighten the noose around the
Islamic State-held city of Mosul in northern Iraq, they face a cunning and murderous foe who has had two years to dig in and is fighting back with a ferocious campaign of scorched-earth tactics, suicide bombers, toxic sulphur-laced clouds, a morale-sapping cyber campaign and high-grade bombs, some of them assembled by slave labor, that could remain a danger for years to come.
The Islamic State's ordnance production is no longer restricted to a small cadre of bomb-makers, veterans of the jihadist wars, but is run on what military experts say is an industrial scale.
Iraqi and Kurdish officials say this has been achieved through a network of factories using some of the thousands of slaves IS has amassed since 2014 when it seized one-third of Iraq.
"Islamic State went through its own industrial revolution," observed Emmanuel Deisser, director of Sahan Research, a British-based security think tank hired by the security council of Iraq's semi-autonomous Kurdish region to analyze the bomb threat of the Islamic State.
"It got a workforce to produce a seemingly endless high-quality stream of death machines and improvised explosive devices," he told the Financial Times.
The danger from the thick carpets of bombs and booby traps IS has laid in and around Mosul goes well beyond the current campaign. Military experts expect Mosul and other towns still to be liberated will remain death traps for years because it will take that long to find and disable the hidden bombs — all part of the jihadists' scorched-earth policy.
This produces a climate of fear that could impede efforts to bring the city under state governance once again and becomes a major obstacle to the massive task of reconstruction.
"In the areas where it ruled for long enough to seed them with bombs, the group has created a dark, parallel universe, where even the most mundane object can kill," Emma Graham-Harrison of the Guardian, a British newspaper, reported from the war zone.
"A toy, a playing card and an abandoned watch are all detonators designed to spark the acquisitive curiosity of a returning civilian, who would be maimed or murdered by the explosion."
Graham-Harrison, who is accompanying Kurdish Peshmerga fighters advancing on Mosul from the east and dealing with IS ambushes and killer booby traps day after day, defined with chilling clarity a nightmarish world in which "an ordinary hose lying across a road is another simple but ingenious detonator.
"A bundle of old clothes, which a dog or a cat could step across without harm, would have exploded if someone had picked it up to reclaim or throw away. A pile of mud and stones is a concealed mortar.
"A discarded piece of plywood would have activated a bomb when it was picked up or kicked aside, as a ball bearing rolls down a tube to complete the [firing] circuit. Duct tape, a lever and a trip wire turn a door into a deadly weapon," she reported.
Since August 2014, when the U.S.-led coalition launched its air campaign against IS in Syria and Iraq, more than 15,800 airstrikes have been carried out and the jihadist fighters have learned to dig deep for protection. U.S. and Iraqi military reports say the tunnel network is immense.
Some tunnels, equipped with air conditioners and electric lighting, run several miles. This has produced a massive subterranean dimension, largely impervious to airstrikes, to an already complex war.
Unleashing simultaneous or linked suicide attacks using trucks that have heavy armor plating welded on to make them almost invulnerable has become an IS trademark and these slowdown operations have taken a heavy toll.
Iraqi troops and the Kurdish Peshmerga have learned how to break up these fearsome assaults but enough of the suicide attackers invariably get through to wreak havoc. These operations remain one of IS's most effective tactics.
As IS battles to hold onto its last urban stronghold in Iraq, it seems likely that the jihadist fighters are disguising themselves as refugees to infiltrate towns and villages around Mosul to ambush the advancing state forces when they least expect it.
An attack in the oil city of Kirkuk, 37 miles from the main line of advance on Oct. 21, four days into the offensive, is a case in point.
An IS force of about 60-70 fighters armed with heavy weapons struck simultaneously in several districts of the town, killing more than 100 soldiers in two days of fierce combat. Most of the attackers were killed but the ambush underlined how intense the fight for Mosul is likely to be.
When Iraqi troops stormed the village of Badana al-Sagheera, 18 miles west of Mosul, two days into the offensive, the IS fighters fled within hours — but left behind booby-trapped buildings and an elaborate tunnel system.
Kurdish fighters recounted how hours after the fighting ended, a screaming suicide bomber sprang out of a heavily screened tunnel opening and blew up a Peshmerga general and his aides.
In one house, Kurdish fighters found a room piled with air conditioners and washing machines from which the jihadists had ripped out timers to use in bombs.
Maj. Mohammed Kareem, a Peshmerga battalion commander, told the Financial Times that the way IS is fighting means that "after liberation, we'll need six months to stabilize the city. The tunnels are a tool that ISIS can use to keep infiltrating."
Amid fears IS will use chemical weapons it produces in its own underground factories, the jihadists set fire to the state-owned Mishraq sulphur plant, 25 miles south of Mosul, on Oct. 20, creating a thick, noxious cloud of sulphur dioxide that was intended to slow the advance on Mosul.
Winds blew it over the Qayyarah air base, the command center for the advance where U.S. troops are deployed, forcing them to don gas masks. The potentially lethal cloud mixed with choking black smoke from oil fields set alight by IS weeks earlier as part of their strategy of destruction.
Sulphur dioxide can be lethal. Iraqi authorities reported two civilians died and hundreds suffered from breathing problems.
In another tactical innovation in its asymmetric strategy against an enemy that outnumbers it by at least 10 to 1, IS intensified its cyberwar operations to unprecedented levels, greatly extending the Internet campaign of psychological warfare it employed so skillfully in splintering the superior forces of the Iraqi Army when the jihadists seized Mosul in June 2014.
Ali Aghuan of Bayan University in Erbil, capital of Iraq's semi-autonomous Kurdish region, said IS "has established a huge electronic army working on multiple objectives and separate missions within the framework of a comprehensive strategy [that] involved advanced forces specialized in military, social, economic and psychological affairs."
This "virtual warfare," Aghuan explained, has played a key role in IS's military successes and is now being used extensively in a bid to undermine the morale of the troops moving on Mosul and to undercut Baghdad's military superiority on the battlefield.
"These [IS] soldiers are the ones to lead the mission targeting individuals through media in order to shape their way of thinking," Aghuan said in a report on the Fikra Forum website.
"There are multiple dimensions to asymmetric warfare, and ISIS has established a number of units that specialize in cyberspace and virtual warfare that involve multiple psychological and moral dimensions...
"These tactics have been successful because Iraqi forces have not been trained on such types of combat and Iraq has had no interest whatsoever in the cyber field or any modern Internet attacks."
In the latest development, IS is now using tiny, hard-to-detect drones to drop explosive devices.
Known as unmanned aerial systems, or UAS, they include one variant that is a flying bomb called a Trojan Horse. One of these benign-looking craft landed near Kurdish troops in northern Iraq and then exploded, killing four men, Lt.-Gen. Stephen Townsend, commander of U.S. forces in Iraq, disclosed.
"We expect to see more of this," he warned.
