The Syrian Democratic Forces (SDF) claim that they have captured the El Omar oilfield, Reuters reports.

“Our forces managed to liberate the fields without notable damages,” a spokeswoman for the SDF told Reuters.

The field had been under the control of the Islamic State.

El Omar is Syria’s largest oilfield. Prior to its capture by the Islamic State, the field was estimated to produce 9,000 barrels per day (b/d), according to the Washington Post.  The field was subject to Russian and US airstrikes and its current capacity is unknown.

In 2015, Syria’s known oil reserves stood at 2.5 billion barrels, the Washington Post reports.

The SDF is a Kurdish-led militia that is allied with the US and its coalition against the Islamic State.