A mustard chemical warfare agent has been found in Mosul alongside Russian surface-to-surface missiles, an Iraqi officer said Saturday, according to the Associated Press. The discovery has renewed concerns of the Islamic State developing chemical weapons, something the extremist group has reportedly been trying to do in Iraq. The report by AP cites Iraqi special forces Brig. Gen. Haider Fadhil as saying French officials confirmed that the chemical found was a mustard agent after testing it earlier this week. No further details on the chemical were available, but Fadhil said Iraqi forces were exposed to the site for about ten minutes and did not exhibit any symptoms. “We know that they were using this place to experiment with chemical weapons,” Fadhil said. He said he believes the site, about 1.2 miles from the Tigris, was meant to remain secret from Mosul residents who might alert the Iraqi military of the chemical. The chemical was found alongside a warehouse full of missiles with Russian inscriptions.