The Syrian Democratic Forces (SDF) said they gained control of Al-Omar oil field, one of Syria’s largest, on the eastern bank of the Euphrates river.
With air strikes and special forces from the US-led coalition, the SDF has been battling Daesh in oil-rich Deir Ezzor, bordering Iraq. The SDF alliance of Kurdish and Arab militias has been focused on territory east of the river, which bisects the province.
The Syrian army, with Russian air power and Iran-backed militias, has been waging its own separate offensive against Daesh militants, mostly to the west of the river.
The US-led coalition and the Russian military have been holding deconfliction meetings — to prevent clashes between planes and troops — though the offensives have sometimes come into conflict.
Al-Omar oil field lies some 10 kilometers north of the town of Al-Mayadin, which government forces and their allies took earlier this month.