Kurdish forces in Iraq are investigating two other possible chemical weapons attacks by the Islamic State group, a top official has said.
The two purported chemical weapon attacks resemble one claimed Saturday by Kurdish officials who say an independent laboratory concluded the militants used chlorine gas against its peshmerga forces in a January 23 truck suicide attack. However, their claims were not immediately verified by international authorities.
Iraqi officials and Kurds fighting in Syria have made similar allegations about the militants using the low-grade chemical weapons against them. The Islamic State group, which controls a third of Syria and Iraq in its self-declared caliphate, has not commented on the claims.
General Aziz Wesi, in charge of a Kurdish special forces brigade, told journalists that authorities declined to immediately discuss the two newly announced attacks when they happened on December 26 and January 18 out of fears of causing a panic.
Kurdish officials have offered footage of the aftermath of the December 26 attack, which shows men coughing and pouring water over their heads after another suicide truck bombing that authorities say wounded some 60 men.
"I put a wet scarf on my face because when I saw the gas, I felt it," said Captain Mohammad Sewdin, who leads the Kurdish special forces unit targeted in the December attack.
"I was afraid it might be something like (chemical weapons). So I told my men to do the same."
Capt Sewdin said he was temporarily blinded for six hours after the attack and coughed up blood. He and others were hospitalised. On Saturday, the Kurdistan Region Security Council offered video and lab results it said proved the Islamic State group used chlorine in the January 23 suicide truck bomb.
There has been no independent confirmation of any of the Kurds' claim. Peter Sawczak, a spokesman for the Organisation for the Prohibition of Chemical Weapons - which has monitored Syria dismantling its chemical weapons stockpile, said that his group had not been asked to investigate the January 23 attack.
Chlorine, an industrial chemical, was first introduced as a chemical weapon at Ypres in World War I with disastrous effects as gas masks were not widely available at the time. While chlorine has many industrial and public uses, as a weapon it chokes victims to death. Most nations banned its use in war in the Geneva Protocol of 1925.
In the Syrian civil war, a chlorine gas attack on the outskirts of Damascus in 2013 killed hundreds and nearly drove the US to launch airstrikes against the government of embattled President Bashar Assad. The US and Western allies accused Assad's government of being responsible for that attack, while Damascus blamed rebels.
There have been several allegations that the Islamic State group has used chlorine previously.
In October, Iraqi officials claimed Islamic State militants may have used chlorine-filled cylinders during clashes in late September in the towns of Balad and Duluiya. Their disclosures came as reports from the Syrian border town of Kobani indicated that the extremist group added chlorine to an arsenal that already includes heavy weapons and tanks looted from captured military bases.