A video posted last month and shot on the outskirts of Mosul purportedly by the Islamic State, shows the insurgent group targeting and destroying an Iraqi driven U.S.-made M1 Abrams main battle tank with an unknown type of ATGM. (TWP)

The Iraqi march up to Mosul has been a weeks-long slog of Islamic State sniper fire, roadside bombs and suicide attacks. The tens of thousands of troops, buoyed by U.S. airstrikes and advisers, have made progress, though — stalling on some fronts but piercing into the city on others.

While the Islamic State’s tactics have been a hodgepodge of diversionary skirmishes and concerted counterattacks, the desert terrain outside Mosul has allowed the group — also known as ISIS and ISIL — to effectively use antitank guided missiles, or ATGMs, in its defense of the city’s approaches. Though it is hardly a new tactic on the recent battlefields in Iraq and Syria, the large offensive has produced footage of the weapons in use against U.S.-made vehicles that — in recent years — have not had to contend with them.

[U.S.-made missile goes up against one of Russia’s most advanced tanks]

A video posted last month and shot on the outskirts of Mosul, purportedly by the Islamic State, shows the insurgent group targeting and destroying an Iraqi-driven, U.S.-made M1 Abrams main battle tank with an unknown type of ATGM. The M1A1 and M1A2 Abrams are considered some of the best tanks in the world, with heavy armor, high speeds and a gyroscopically stabilized 120mm main gun. U.S. forces have used them extensively since they entered service in the 1980s. The tank in the video is probably an export version of the Abrams tailored specifically for Iraqi forces.

The missile strikes the rear of the turret — where the armor is weaker — and seems to have entered the ammunition storage compartment. The tank immediately bursts into flames as the tank rounds inside explode, known as “cooking off,” according to a Marine Abrams tank commander who had viewed the video. While the strike looks catastrophic for the four-man crew inside, the tank is designed to mitigate such a strike. According to the commander, who spoke on the condition of anonymity because of his active-duty status, it appears that the explosion triggered “blowoff” panels on the top of the ammo compartment that are meant to channel the exploding ordnance up and out of the tank. The crew probably survived unless the missile pierced the turret of the tank. He added that with the open hatch on the turret, however, it is possible that the flames could have been fed back into the turret.

The strike on the Iraqi tank highlights the growing proliferation of a weapons system in limited use by insurgents in Iraq and Afghanistan during the height of the U.S.-led wars there but is rapidly solidifying itself as an enduring threat on the battlefields of the future.

“The ATGM is our biggest threat on the battlefield,” the commander said.

In Syria, the United States has pumped the aging but ubiquitous U.S.-made TOW antitank guided missiles to Syrian opposition groups, which have used them for striking a variety of targets, including Syrian government tanks and stationary Russian helicopters. Russian ATGMs such as the Kornet and Fagot also have been widely used. The weapons usually take a small crew to operate and are considerably bulky. But what they trade off in size they make up with in range and accuracy. With their wire or laser guidance systems, some ATGMs can hit targets miles from their launch site if the terrain is favorable.

To deal with the increasing threat of ATGMs and more-advanced ammunition types, countries have taken measures to bulk up their tanks with special armor or modify them with systems that basically defeat incoming projectiles with counterprojectiles or by jam their targeting systems. The former is known as reactive armor; the latter is called an active protection system, or APS. While the U.S. military is looking at a number of APS options for its armored-vehicle fleets, Israel already uses what is called the Trophy system, an APS that is covered extensively in this National Interest piece. Russia uses the Shtora APS mounted to some of its more modern T-90 battle tanks, some of which have been spotted in Syria.

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