Islamic State (Isis) jihadists have renewed chemical attacks on Kurdish fighters in the last week as allies prepare to retake the terrorist group's stronghold of Mosul in Iraq. Kurdish forces, also known as Peshmerga, say they were attacked twice in one week by a "yellowish gas" in northern Iraq, with soldiers left struggling to breath and choking.

The most recent attack, on a village near the town of Gwer south-east of Mosul, was reported on Tuesday (19 April), with eight soldiers affected. Another chemical attack, believed to be chlorine, was launched close to Gwer on Sunday, seeing one Peshmerga fighter reportedly killed with four others injured.

The fallout was witnessed by former British Army colonel Hamish de Bretton-Gordon, who now helps train forces like the Peshmerga and who used to be a commanding officer of the UK's Chemical, Biological, Radiological and Nuclear (CBRN) regiment.

"Isil (Islamic State of Iraq and the Levant) have attacked the Peshmerga with chemical weapons at least 10 times in the last six weeks alone," he told The Telegraph. "It is clear that Isil units do have chemical weapons in forward positions, and are very happy to use them." Speaking about Tuesday's attack, he added: "Soldiers talked of a yellowish gas and those unable to flee suffered from difficulty in breathing and choking. On the face of it this sounds like chlorine."

The military use of chlorine or mustard gas – both said to be in Isis commanders' arsenal – is banned under international law.

The UK government said there were now numerous "credible reports" the terrorist group had adopted chemical warfare. Last month, an attack allegedly carried out with the use of chemicals on the Iraqi town of Taza saw a three-year-old girl killed and hundreds others injured.

In February, Isis launched another suspected chemical attack against dozens of Peshmerga militants who suffered from vomiting, dizziness and difficulty breathing after improvised rockets struck. The strike landed in an area south of Sinjar, a north-west town about 50km (31 miles) from the Syrian border, according to the Kurdistan Region Security Council (KRSC).

Retaking Mosul

It comes as Iraqi and Peshmerga forces, with help from the Western allies, prepare to retake the Isis stronghold of Mosul, which was captured in June 2014. President Obama said in an interview this week he expected the city to return to the control of the Iraq government by the end of the year.

The threat of chemical weapon attacks in denting that goal has been suggested as more psychological than military. "It's a legitimate threat. It's not a high threat. We're not, frankly, losing too much sleep over it," US Army Colonel Steve Warren said.

Bretton-Gordon added: "The fear of chemical weapons is the real terror of war. Less than 0.5% of casualties during World War I were attributed to chemical weapons, yet the Great War has become synonymous with their use. The current conflict in Syria and Iraq depicts a similar picture.

"As Isil loses more ground and gets pushed back towards Raqqa, it will use every means at its disposal to hold off defeat. In the aftermath of Taza and Sinjar attacks, chemical weapons could be employed again."

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