Deputy Prime Minister Numan Kurtulmus said Monday Turkey wants the drive to oust Islamic State jihadists from the Syrian city of Raqa to begin after operations in Iraq's Mosul and a Turkish-backed mission in northern Syria are over.

"It would be right, militarily and strategically, to conduct this Raqa operation after the Mosul operation and Turkey's Euphrates Shield operation have ended," he told reporters in Ankara.

Last week US Defence Secretary Ashton Carter said operations for the "isolation" of Raqa, the de-facto capital of IS' self-declared caliphate, should begin in conjunction with the assault on Mosul.

An offensive by Iraqi and Kurdish peshmerga forces to free Mosul, Iraq's second biggest city, began in mid-October with air support from the US-led coalition.

Meanwhile Turkey is continuing with an operation called Euphrates Shield, launched on August 24, in which it is supporting opposition fighters in northern Syria with tanks and air strikes.

The Ankara-backed fighters comprise various brigades rather than one organised force, according to experts.

So far, the rebels have captured the IS stronghold of Jarabulus and retaken the symbolically important town of Dabiq.

Turkish President Recep Tayyip Erdogan said last week that the rebels would target Raqa after advancing towards the city of Al Bab in northern Syria and taking Manbij, recently captured by Syrian Kurdish YPG militia.

Euphrates Shield has two main goals: to clear IS elements from the Turkish-Syrian border and halt the westward advance of the YPG.

Last week Ankara conducted air strikes against People's Protection Units (YPG) positions to stop their advance towards Al Bab, Turkish media said.

Ankara views the YPG as linked to the outlawed Kurdistan Workers' Party (PKK), which has been waging an insurgency inside Turkey since 1984.