Iraqi security forces have been working to reclaim territory taken by the Islamic State since the group carried out a massive land grab in 2014. In this image, Iraqi forces work to capture the town of Zankoura near Ramadi in June. A Pentagon spokesman on Monday said the Islamic State "would love to use chemical weapons" against Iraqi forces and U.S. forces as the key battle for Mosul draws near. File Photo by Abbas Mohammed/UPI | License Photo

WASHINGTON, Sept. 27 (UPI) -- Navy Capt. Jeff Davis, a spokesman for the Department of Defense, said the Islamic State "would love to use chemical weapons" following a suspected mustard gas attack in Iraq.

The Islamic State is suspected of firing a shell containing a mustard gas agent last week that landed near Iraq's Qayyarah Air Base, where U.S. and Iraqi troops are operating ahead of the battle for Mosul. No one was injured.


On Monday, Davis said the Islamic State "knows no boundaries when it comes to their conduct on the battlefield" when referring to the mustard gas attack the militant Islamist group is accused of carrying out. The shell, categorized as either a rocket or artillery shell, was rudimentary and non-lethal, Davis said, adding that using the weapon violates international law and standards.

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Davis said the Islamic State, also known as Daesh, ISIS and ISIL, has launched chemical weapons containing mustard gas at least "a couple dozen" times. Iraqi security forces, aided by a U.S.-led anti-Islamic State coalition, are preparing a ground offensive to retake Mosul, once Iraq's second-largest city.

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The Kurdish Peshmerga helped Iraq secure areas surrounding Mosul for months but will not participate in the offensive to retake Mosul directly.

Davis said the Islamic State could also use chemical weapons against Iraqi security forces and the U.S. troops in Iraq as the Mosul battle looms.

"We recognize this is real. They're dead-set on it -- they would love to be able to use chemical weapons against us, against the Iraqis as they move forward," Davis said during a Pentagon press conference. "We are making every effort to make sure that we're ready for it."

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Officials believe the Islamic State, which could have up to 4,500 militants in Mosul, has rigged the city with improvised explosive devices, which could contain chemical agents.

"We want to make sure that the Iraqi security forces and that the Peshmerga have the ability to detect this and to defend against it," Davis added. "But I think we can fully expect, as this road towards Mosul progresses, ISIL is likely to try to use it again, so this is something that could happen again."