In-fighting between Turkish and Kurdish militias in northern Syria is complicating plans to drive their mutual enemy ISIL from the city of Raqqa.

Turkish jets and armour, supporting Syrian rebels, have struck Kurdish fighters in recent days. US Defense Secretary, Ash Carter, announced an operation will begin within the next few weeks to combat militants in Raqqa. He said that launching simultaneous anti-ISIL operations in Raqqa and Mosul "has been part of our planning for quite a while".