A rocket attack by Islamic State militants in northern Syria caused symptoms of "chemical gas" in 22 Syrian rebels, state media cited the Turkish armed forces as saying on Sunday.
The attack targeted Turkey-backed rebels who have been besieging the Islamic State-controlled town of al-Bab for days. Al-Bab is a major target in the "Euphrates Shield" operation to push the jihadists away from the Syrian side of the Turkish border.
The Turkish military said the rocket attack was in Syria's Haliliye area, according to state-run Anadolu agency. It did not specify when the attack occurred.
Media reports said Turkish AFAD emergency relief teams had conducted various tests on the affected rebels for traces of chemical materials at a hospital in Turkey's border province of Kilis.