Isil uses mustard gas in attack on American troops
Isil has used chemical weapons against US troops, in what is thought to be the first such attack on American servicemen since the First World War.
The jihadists fired a rocket containing suspected mustard gas at an airbase in Qayyarah, south of Mosul, where the troops are supporting Iraqi forces.
US officials said the soldiers took decontamination showers and were as yet not suffering any symptoms from the exposure. Initial tests carried out by US forces in the field revealed a positive result for toxic chemical agent mustard, a banned substance which can cause burns and breathing difficulties.
A second test came back negative and a third sample has been sent to a laboratory for definitive analysis.
"It was mustard agent in a powderised form - the same thing we have seen [Isil] use to little effect many times in the past in both Syria and Iraq," said navy captain Jeff Davis, a Pentagon spokesman, adding that the agent was "low-grade" and poorly weaponised. "The device, likely a rocket or mortar, was imprecise and crude."
Nevertheless, the use of chemical weapons will be of great concern to ground forces as they advance towards Mosul, which was overrun by Isil in the summer of 2014 and continues to be a stronghold for the militants.
Just 50km away from the city, several hundred US troops are operating out of the airbase in Qayyarah, after it was recaptured from the jihadists in July by the Iraqi army.
The troops based there are expected to begin the much-anticipated battle for Mosul next month. Mosul, with a population of around 1.2 million people, is the largest urban area under the jihadists' control. The coalition and its Iraqi partners are expecting Isil to put up a fierce defence.
Isil has long been suspected of making and using crude chemical weapons in Iraq and Syria. Some experts also believe several hundreds tonnes of undeclared chemicals in President Bashar al-Assad's stockpile, which was handed over to the Organisation for the Prohibition of Chemical Weapons (OPCW) in 2014, has made it into the terror group's hands.
US-led coalition warplanes have targeted and destroyed several of Isil's chemical stores in northern Iraq, but many of its weapon-making facilities have gone underground and moved to residential areas of Mosul to avoid air strikes.
While it is the first chemical attack against US troops, there have been 20 documented cases of chemical weapons being used against the Kurdish Peshmerga army, which has been moving in on the city from the east for the past few months.
Colonel Hamish de Bretton Gordon, former commanding officer of the UK Chemical, Biological, Radiological and Nuclear Regiment (CBRN), who has been advising and training the Peshmerga in Kurdistan, said troops should be prepared for bigger and more lethal chemical attacks.
He said Peshmerga commanders have intelligence that Isil has rigged a chemical plant at Misraq with explosives. The plant lies just 40km south of Mosul and 10km north of where the US troops are at Qayyarah. An explosion at Misraq, which holds thousands of tonnes of sulphur dioxide and hydrogen sulphide, could be catastrophic. Col de Bretton Gordon predicts the fallout of such an explosion could have a radius of 10-20km - meaning Iraqi, and any supporting US, forces would be at risk. (© Daily Telegraph London)