The Islamic State group used chemical weapons against Iraqi forces taking part in the operation to recapture Mosul, injuring some security personnel, the military said on Sunday.
IS has periodically carried out attacks using chemical weapons, but both the toll and the impact on military operations has been minimal and the jihadists' bombs and bullets are far deadlier.
"The Daesh terrorist gangs tried to block the advance of our forces by using shells filled with toxic chemical material, but the effect was limited," Iraq's Joint Operations Command said in a statement, using an Arabic acronym for IS.
The attack on Saturday did not result in any deaths but did cause "limited injuries" among security personnel, the military command said.
The statement said that the forces attacked were part of the massive operation aimed at recapturing the city of Mosul from IS, but did not specify if the attack took place in or outside the city.
Iraqi forces are fighting to recapture west Mosul from IS after retaking the eastern side earlier this year, while soldiers and pro-government paramilitaries are also operating west of the city as part of the operation.
The jihadist group overran large areas north and west of Baghdad in 2014, but Iraqi forces backed by US-led air strikes have since regained much of the territory they lost.
In addition to parts of western Mosul, IS also holds part of Iraq's Kirkuk province as well as areas in the country's west.
© 2017 AFP