The U.S. led air strike campaign against Islamic State (IS) Wednesday destroyed 15 oil refineries in Syria operated by the extremist militant group.
Three modular oil refineries were hit during an airstrikes in the Al-Hakasah province, the Wall Street Journal said.
The U.S. Defense Department said Wednesday that airstrikes also hit 12 small modular oil refineries in remote areas of eastern and northeastern Syria.
IS seized the refineries during its military campaign against the Syrian government.
Government officials believe that IS controls six out of the ten oil fields in Syria and four small fields in Iraq.
IS produces an estimated 50,000 barrels per day in Syria and 30,000 barrels per day in Iraq that can generate a combined profit of up to $6 million a day.
The extremist group raises funds by selling the oil products processed at its refineries on the black market and to smugglers that sell the product on the grey market in Turkey, Iran and Jordan.
Some of the oil is also sold to the Syrian government.
The Pentagon said the strikes were meant to destroy the refineries and cut funding off to IS and were “not necessarily to kill militants.”