Erdogan says Turkish military operation will target Raqqa

Erdogan said the rebels were now advancing on the important city of al-Bab to clear Islamic State group elements. After retaking the city, they will target Manbij, captured by Syrian Kurdish militia in August, and "then we will go towards Raqqa".

Raqqa, the de facto capital of the Islamic State, has long been the next target in the fight against the extremists but there is a debate on how the offensive would look on the ground.

The US-led coalition against IS is likely to provide air support but Turkey opposes the involvement of any Syrian Kurdish militias.

Since August 24, Turkish tanks and special forces have been inside northern Syria providing support to opposition fighters in an ambitious operation to remove IS militants from the entire border area.

The Turkey-backed rebels comprise different Syrian opposition brigades rather than a single organised force, according to experts.

The operation dubbed "Euphrates Shield" has another purpose: to halt the westward advance of the Syrian YPG Kurdish militia.

Ankara says the People's Protection Units (YPG) and Kurdish Democratic Union (PYD) are linked to the outlawed Kurdistan Workers' Party (PKK) waging an insurgency in Turkey since 1984.

The PKK is proscribed as a terrorist organisation by Turkey, the European Union and the United States.

In August the Kurdish-led Syrian Democratic Forces (SDF), a US-backed alliance of about 30,000 Kurdish and Arab fighters, captured Manbij from IS.

But Erdogan has repeatedly said any operation to retake Raqqa cannot be done with YPG elements and on Thursday, said the Turkish operation would target Manbij as well.

He later said he told US President Barack Obama in a telephone conversation on Wednesday that he opposed any YPG or PYD participation.

"We do not need terrorist organisations like the PYD/YPG... I said, 'come let's remove Daesh (IS) from Raqqa together. We will sort this out together with you'. We have the strength," he said, referring to the Turkey-backed rebels.

Erdogan also said that Turkey would not allow the northern Iraqi district of Sinjar to become a new Qandil, referring to the mountainous area in Iraq's north where the PKK has bases.

"Sinjar is on its way to becoming a new Qandil. We will not allow (this) because the PKK is there," hinting at possible Turkish military intervention.