The Pentagon released video and images of airstrikes targeting oil refineries controlled by the Islamic State group in eastern Syria late Thursday.

The United States-led airstrikes on 12 oil refineries near the towns of Al Hasakah, Al Mayadin and Abu Kamal were carried out late Wednesday and early Thursday, according to a document released by the Pentagon.

At least 19 people were reportedly killed in the airstrikes that targeted the main revenue stream of the Sunni extremist group.

“These small-scale refineries provide fuel to run ISIL operations, money to finance their continued attacks throughout Iraq and Syria, and they are an economic asset to support future operations,” Pentagon spokesperson Rear Admiral John Kirby said in a statement on Thursday.

The videos released by the US Department of Defense showed overnight airstrikes on the Jeribe and Mayadin refineries. Before and after images also showed the aftermath of the airstrikes. isis oil fields Photos released by the U.S. Department of Defense on Sept. 25 show the Jeribe Modular Oil Refinery in eastern Syria before (left) and after air strikes. Photo: U.S. Department of Defense

The Islamic State group, formerly known as ISIS, is believed to control six out of 10 of Syria’s oil fields, including al-Omar, which sits on the border with Iraq and four small fields in Iraq, according to media reports. isis oil fields2 A map of Syria depicting the ISIS-controlled oil refineries targeted in the U.S.-led airstrikes on Wednesday. Photo: U.S. Department of Defense

“Producing between 300 and 500 barrels of refined petroleum per day, ISIL is estimated by some regional organizations to generate millions of dollars of revenue from these refineries,” Kirby said, adding that the aim of the airstrikes was to cut off this revenue stream, which, according to some estimates, generates nearly $2 million daily for the Islamic State group.