U.S.-backed Syrian militias 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 Syrian Democratic Forces (SDF) will formally declare the operation on Saturday, with the aim of pushing ISIS back from northern parts of Deir al-Zor, the official said.
They will launch the assault from the south of YPG-controlled Hasaka, the official said, part of a wider offensive to drive ISIS out of Raqqa city and territory to its southeast.
With U.S.-led air cover and special forces on the ground, the alliance of mostly Kurdish and Arab militias is fighting to seize Raqqa, 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 toward the Euphrates River from the east of the province, which borders Iraq.
The operation will likely bring the U.S.-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.
The eastwards march has on occasion brought the Syrian army and its allies into conflict with U.S.-backed forces.
Still, the rival campaigns have mostly stayed out of each other’s way, and the U.S.-led coalition has stressed it is not seeking war with Damascus.