A fighter from Deir al-Zor military council which fights under the Syrian Democratic Forces (SDF) holds the council’s flag in the village of Abu Fas, Hasaka province, Syria September 9, 2017.

:: US-backed militias said they captured a major oil field in Deir al-Zor province on Sunday, pressing their offensive against ISIS fighters in eastern Syria.

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 ISIS in oil-rich Deir al-Zor, 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 ISIS 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 km north of the town of al-Mayadin, which government forces and their allies took earlier this month.