U.S.-backed fighters launched a new offensive on September 9 against the extremist Islamic State (IS) group in eastern Syria, increasing the possibility of conflict with rival, Russian-backed government forces, running their own operations in the same area.
Bordering Iraq, the oil-rich Deir al-Zour province is a key prize for many, including the Russian-backed Syrian troops fighting for its western half.
It has become the latest epicenter of the war against IS.
The predominantly Kurdish Syrian Democratic Forces (SDF) announced that their Deir al-Zour Military Council have launched operation “Jazeera Storm” to oust IS militants from Deir al-Zour Province.
Abu Khawlah, who heads the SDF's Military Council, said that SDF forces will now aim to clear the IS militants from territory east of the Euphrates River.
Khawlah said forces had begun to push IS out of territory in Hasakeh Province and further south in Deir al-Zour.
This week, Syrian troops and their Iranian-backed allies reached Deir al-Zour, breaking a nearly three-year siege by IS on government-held parts of the city. Government forces are trying to reach a nearby air base, still surrounded by IS militants.
The SDF are also fighting against IS militants over the jihadists’ de-facto capital city, Raqqa, in north Syria. Ground and air support have been provided by the U.S. military.
Since 2014, IS has held territories in Deir al-Zour and about 60 percent of the provincial capital Deir al-Zour as well as a pocket of territory near Hama and Homs in the west of Syria.
IS militants have lost more than half of Raqqa and all of Iraq’s second city, Mosul.
The offensive to retake the northern Syrian city of Raqqa was launched by the SDF in early June and forces have already seized around 65 percent of the city.
The coalition has carried out airstrikes against IS in Syria since 2014 and is now helping the SDF to retake Raqqa from IS militants.
The September 9 announcement came as Russia-backed Syrian regime forces were waging a separate offensive to remove IS from Deir al-Zour city.
"We are not coordinating with the regime or with Russia. We are coordinating with the international coalition," said Khawlah.
However, the coalition, the SDF, Syria’s government, and Russia have agreed on a "de-confliction line” in northeast Syria to prevent clashes.
The coalition said the line runs from Raqqa Province southeast along the Euphrates River towards Deir al-Zour.
"The de-confliction line with the Russians is necessary in the complex and congested battlespace over eastern Syria," coalition spokesman Colonel Ryan Dillon said.
Khawlah said the U.S.-led coalition air strikes helped forces advance around 30 kilometers in their first clashes.
Earlier on September 9, Syrian state TV announced that the army and its allies recaptured an oil field from IS near Deir al-Zour city.
The Teym oil field is located in a desert south of Deir al-Zour.
Government forces also captured part of a main highway running from Deir al-Zour to the city of Al-Mayadeen, downstream along the Euphrates River, where IS militants have retreated, the Syrian Observatory for Human Rights monitoring group said.
That advance would block potential IS reinforcements from Al-Mayadeen, which is close to the Iraqi border.
With reporting by AP and AFP