The US backed Syrian Democratic Forces (SDF) rejected on Wednesday a Turkish army statement that ISIL was present in the Afrin region of northwestern Syria, where Ankara launched an offensive four days ago which has raised international concern.
"The whole world knows Daesh is not present in Afrin," Redur Xelil, a senior SDF official, told Reuters. He said the Turkish military had greatly exaggerated SDF casualties, though he declined to say how many had been killed.
Ankara launched a military offensive into Afrin, a Kurdish enclave of Syria, claiming it an "anti-terrorist campaign" targeting a US-backed Kurdish group, the People's Protection Unit (YPG).
The Turkish military said on Tuesday that at least 260 YPG and ISIL fighters had been killed in its operation.
President Recep Tayyip Erdogan is justifying the strikes as Ankara's right to self defence.
Syrian Kurdish leaders called on civilians to take up arms to defend the Afrin enclave against a continuing Turkish assault.
Mr Xelil also said the SDF had killed tens of Turkish forces and allied Free Syrian Army fighters, but said he did not have a precise figure.
Turkey sees the YPG - the most powerful faction within the SDF - as an extension of a Kurdish group that has waged a decades-long insurgency in southeastern Turkey. It has long said it will not allow the Kurdish fighters to control a strip of Syrian territory on its southern border.
Meanwhile, US president Donald Trump is expected to raise concerns with Mr Erdogan in a phone call expected on Wednesday about Ankara's offensive, a senior US official said.