Kurdish forces in northern Iraq who are fighting the so-called ’Islamic State of Iraq and the Levant’ (ISIL) takfiri group were attacked with chemical weapons a few days ago.

Kurdish forces in northern Iraq who are fighting the so-called 'Islamic State of Iraq and the Levant' (ISIL) takfiri group were attacked with chemical weapons a few days ago, the German defense ministry said on Thursday.

"There was a chemical weapons attack" southwest of Arbil, a ministry spokesman said, adding that some Kurdish fighters suffered respiratory problems while German military trainers were unhurt.

The chemical agent had been delivered with mortar or artillery shells, said the spokesman, who did not say who was suspected of carrying out the attack.

"American and Iraqi specialists from Baghdad are on their way to find out what happened," he added.

Germany has been supporting the Kurdish peshmerga fighters with arms shipments and weapons training since September to back the fight against ISIL, and currently has about 90 personnel on the ground.

"German soldiers were not affected or in danger," the spokesman said. "The protection of our soldiers in northern Iraq is already at the highest level."

ISIL has previously been accused of using chlorine against Kurdish forces in Iraq.

The chemical used had characteristics and clinical effects consistent with a chlorine chemical agent, according to human rights groups.