The US-backed Syrian Democratic Forces are set to announce an operation against ISIS in the north of Deir al-Zor province, a senior SDF official told Reuters on Friday.
The operation, which aims to push ISIS back from northern parts of Deir al-Zor, will be formally announced on Saturday, the official said.
With US-led air cover and special forces, the SDF alliance of mostly Kurdish and Arab militias is battling to oust ISIS from Raqqa city, upstream along the Euphrates river.
Spearheaded by the Kurdish YPG militia, the SDF says it has taken 65 percent of Raqqa city from ISIS.
In the Deir al-Zor assault, the SDF would push towards the Euphrates River from the east of the province, which borders
The operation will likely bring the US-backed militias into closer proximity with the Syrian military and allied forces, who have advanced on Deir al-Zor city.
The Syrian army reached its enclave in Deir al-Zor city this week, on the western bank of the Euphrates, breaching an ISIS siege that had lasted three years.
With the help of Russian air power and Iran-backed militias, the advance capped months of steady progress east against ISIS across the desert.
The eastwards march has on occasion brought the Syrian army and its allies into conflict with US-backed forces.
Still, the rival campaigns have mostly stayed out of each other’s way, and the US-led coalition has stressed it is not seeking war with Damascus.