attacked Kurdish forces multiple times even as they have suffered mounting losses at the hands of IS.

US defence officials announced on Thursday that they were brokering talks between the two sides in a bid to prevent any further conflict between them disrupting the campaign against IS.

"This week, we're facilitating joint discussions with Turkey, the SDF and other coalition partners to promote deescalation in the area," said Colonel John Dorrian, spokesman for the US-led coalition battling IS.

The Pentagon chief said that with the offensives against Mosul and Raqa, the coalition had reached "a critical milestone" in its campaign against IS.

Iraqi forces are battling jihadists deep inside Mosul, edging closer to the River Tigris that divides the city.

But seven weeks into the offensive, they still control barely half of itseastern side .

"This is a complex mission that will take time to accomplish but I'm confident that ISIL's days in Mosul are numbered," Carter

said, using an alternate acronym for the jihadist group.

He warned it was unclear what form IS would take after its eventual defeat in Iraq and Syria.

"We must be ready for anything," he said.

Bahrain, Saudi Arabia and the United Arab Emirates have all carried out air strikes against IS in Syria, and Jordan has done so in both Iraq and Syria.

But Carter said there had been "some imperfections" in the regional response to the jihadists.

"Some of the regional powers here in the Middle East have not lived up to the full potential one would expect", he said, without singling out any country.

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