US-backed Arab and Kurdish military forces are set to launch an offensive to take Raqqa, a stronghold of Islamic State (Isis) in Syria. The Syria Democratic Forces (SDF) will begin an attack within hours, assisted by US-led coalition air strikes. Warnings were issued to civilians to keep away from regions controlled by IS (Daesh) on Sunday (6 November).

The announcement to retake Raqqa was made at a press conference in Ein Issa, north of Raqqa. A statement was read out saying that the 'Euphrates Rage' operation had officially begun, which will involve more than 30,000 fighters engaged in the offensive, reported CBS News.

However, a warning was issued to Turkey by an SDF official, according to Reuters. "Our hope is that the Turkish state will not interfere in the internal affairs of Syria."

The unidentified official said at the news conference announcing the military operation: "Raqqa will be free by its own sons."

The bulk of the fighters in the SDF are made up of the Kurdish YPG forces, the People's Protection Units. Turkey views the YPG with suspicion, claiming they are a terror organisation with links to the Kurdish insurgency taking place in south-eastern Turkey.

President Recep Erdogan's government says it will not accept a role for the Kurds in the retaking of Raqqa. But the US regards the SDF as a key ally and the most effective force fighting against IS.

Commander of anti-Isis coalition forces, Lt Gen Stephen Townsend said there were signs that IS is actively planning in Raqqa.

"We know they're up to something, and it's an external plot," the general told media from his headquarters in Baghdad. "We don't know exactly where they intend to strike. We don't know exactly when. We know this plot-and-planning is emanating from Raqqa. We think we've got to get to Raqqa pretty soon."

On Sunday afternoon, there were no major advances pushing into Raqqa, stated the Syrian Observatory for Human Rights, but Al Jazeera reported that rebel forces were 40-50km outside the city.