A group of experts from the Iraqi government plan to go to the autonomous Kurdish region of Iraq in the upcoming week to investigate allegations insurgents from the Islamic State group used chemical weapons against Kurdish troops, diplomats said Monday, according to Reuters. Kurdistan Regional Government officials in Northern Iraq have reported three chemical attacks this year.

The alleged attacks against Kurdish peshmerga forces have all come in mortar rounds. Should the attacks be confirmed, it would mark the first time chemical agents have been used in fighting in Iraq since the fall of Saddam Hussein's regime in 2003. Kurdish officials said lab tests were positive for the chemical agent chlorine. 

Diplomats told Reuters Iraqi government officials had launched an inquiry to collect their own samples and determine the accuracy of claims ISIS used mustard gas in taking over vast amounts territory in northern of Iraq since mid-2014. The experts were scheduled to go to the Kurdish region this week and investigate three incidents.

"They [Iraqi experts] are going to the Kurdish region this week to determine whether chemical weapons were used or not," a diplomat briefed on the investigation told Reuters. Three incidents were to be investigated, the diplomat added.

The Organization for the Prohibition of Chemical Weapons, a global watchdog organization based in the Netherlands, also is to be briefed on the situation and could carry out its own investigation, Reuters said. 

Chlorine is prohibited under the 1997 Chemical Weapons Convention -- which aimed to eliminate the stockpiling and usage of chemical weapons -- and can prove horrifically deadly if inhaled. It turns into hydrochloric acid upon inhalation and burns the lungs.

Former Iraqi President Saddam Hussein used chemical weapons on the Kurds during his time in power, most notably in a March 1988 attack on Kurdish city of Halabja that killed as many as 5,000 people, the BBC reported. Hussein also used chemical weapons in an offensive in which some 50,000-100,000 Kurds were killed or disappeared.

Fox News reported Pentagon officials believed the Islamic State group used chemical weapons in an August attack on Kurdish peshmerga forces. Officials told the Wall Street Journal the weapons could have been obtained by ISIS militants in Syria where the group controls large swaths of territory.

Known chemical weapons stockpiled in Iraq and Syria have been destroyed under the supervision of the Organization for the Prohibition of Chemical Weapons. Last year Syrian President Bashar Assad agreed to hand over 1,300 tons of chemical weapons to avoid U.S. military intervention after it was reported the government used poison gas in Syria's civil war.