On Sunday, 17 Free Syrian Army (FSA) fighters and two Turkish Special Forces members were injured in an attack launched from Daesh-held Al-Bab in northern Syria.
The Turkish military said in an initial statement that symptoms on the injured soldiers indicated the terror group could be using a chemical weapon in the attack.
Most of the wounded fighters have been taken to a hospital in Turkey's border province of Kilis.
Turkey's AFAD emergency relief teams have conducted various medical tests, including the Chemical Biologic Radiologic Nuclear test, on the affected FSA fighters and said there were no traces of chemical materials.
The Turkish Army also confirmed it with a new statement adding that the attack was conducted by using a gas that causes nausea, headache, burning in some areas especially in the eyes.
Experts say the aim of this kind of attack was to increase psychological pressure rather than physical damage.
The type of gas believed to have been used by Daesh is chloride gas, a gas that does not leave traces and is not detected as a chemical gas. Daesh had used this tactic in different fronts in Syria and Iraq. The terror group used the same kind of gas in its attack on Iraqi army fighting for liberating the northern Iraqi city of Mosul.
The similar attack in Kirkuk's Tazehurmatu had also targeted Turkmen people living in the city. The attack was conducted by using chloride gas.
As the affected fighters show the similar symptoms, it is thought the terror group used the same gas in Al Bab.
Military sources also said that investigations on the rockets fired from Daesh positions had not found any sign of chemical gas.
This kind of attack could be increased, as Turkey's military backed FSA fighters are preparing to enter Al Bab city, sources predicted.
Turkish forces stationed in north of Al Bab have increased measures against chemical gas attacks, by sending chemical protective suits and gas to the area.
Reports claimed the terror group has been using laboratories of the Mosul University to develop chemical-biologic and tactical nuclear weapons.
