Islamist rebels now control the biggest oilfield in eastern Syria, according to reports.
The rebels posted a video that shows a sign at the field that says “Euphrates Oil Company – al-Omar field.”
The fighters took control of the field Saturday.
Syria exported 370,000 barrels a day before the civil war that began in March 2011. It now imports oil from Venezuela and Iran.
The country’s crude oil reserves at the start of 2013 were 2.5 billion barrels — second only to Iraq in the eastern Mediterranean — according to the Oil & Gas Journal.
International oil companies once operating in Syria abandoned operations as violence escalated and Western sanctions on Syria’s energy sector were imposed.
Syria’s shale oil deposits are estimated to range up to 50 billion tons, a Syrian government source said in 2010.
After Saturday’s capture of the eastern field, observers said control over reserves, production, and fuel supplies would give the rebels new leverage over the regime of Bashar al-Assad.
The rebels were reportedly part of the Sunni-led Nusra Front.
More than 100,000 people have reportedly died in the civil war.