Islamic State mortar fragments show traces of chemical arms: U.S. general

WASHINGTON (Reuters) - Fragments from mortars fired by Islamic State militants at Kurdish fighters in northern Iraq earlier this month tested positive in a U.S. military field analysis for sulfur mustard, a chemical weapons agent, a U.S. general said on Friday.

Marine Corps Brigadier General Kevin Killea, chief of staff for operations against the group, said the test was not conclusive proof of chemical weapons use, and the fragments would be further tested to confirm the finding.

Killea said that in addition to the Aug. 11 mortar attack, he was aware of at least two other claims of chemical weapons use by Islamic State. He was not immediately able to say whether any previous testing had supported allegations of chemical weapons use.

In the Aug. 11 incident, mortar shells were fired at Kurdish Peshmerga positions near the town of Makhmur in north-central Iraq, Killea said. Fragments of the shells were collected by the Kurdish fighters and handed over to U.S. forces in the region several days later.

"We were able to take the fragments from some of those mortar rounds and do a field test ... on those fragments, and they showed the presence of HD, or what is known as sulfur mustard," Killea said.

He said sulfur mustard is a Class 1 chemical agent, which means it has few uses outside chemical warfare. Commonly referred to as mustard gas, sulfur mustard is a blistering agent that causes severe, delayed burns to the eyes, skin and respiratory tract, according to the U.S. Centers for Disease Control.

Sulfur mustard can also affect the nervous system, and can cause excess saliva, tears and urine, diarrhea and vomiting. The gas, which can smell like garlic or mustard, can be fatal in large doses.

Killea said the fact that the mortar fragments were delivered to U.S. forces several days after the attack, rather than collected directly by U.S. troops, could lead to some to question whether they had been deliberately contaminated with sulfur mustard.

"It is very important to understand here that is a presumptive field test and it is not conclusive, and what those results tell us is merely the presence of that chemical," Killea said.

He said broader testing should enable the military to confirm the chemical agent that was used and how much was contained in the mortars, and maybe even the source of the sulfur mustard.

He said the testing was would take a couple of weeks to finalize.

(Reporting by David Alexander; Editing by Emily Stephenson, Toni Reinhold)