The Islamic State of Iraq and Syria (ISIS) is no longer relying on oil as its main source of revenue to fund its terrorist activity, according to the Pentagon.
"We know that oil revenue is no longer the lead source of their [ISIS'] income in dollars," Pentagon spokesperson Rear Admiral John Kirby told reporters during a press briefing on Tuesday.
ISIS' loss of income is compounded by its losses on the battlefield as the group has "lost literally hundreds and hundreds of vehicles that they can't replace," Kirby said.
"They've got to steal whatever they want to get, and there's a finite number."
ISIS is instead depending on "a lot of donations" as one of the main sources of income. "They also have a significant black market program going on," Kirby said.
The U.N. Security Council, led by Russia, announced yesterday that it is drafting a legally binding resolution to ratchet up pressure on countries to cut off the cash flow to ISIS militants.
"We are preparing [the resolution] and we hope it'll be adopted by the U.N. Security Council in the coming days," a spokesman for Russia's United Nations mission said.
The announcement comes a day after ISIS released a video showing the captured Jordanian pilot Moaz al-Kasasbeh being torched alive in a cage.
As Jordan, backed by the U.S.-led coalition forces, steps up its fight against ISIS, the Pentagon thinks ISIS is "losing ground."
"They are changing. They are largely in a defensive posture. They aren't taking new ground," Kirby said. "So, they are losing ground. They are more worried now about their lines of communications and supply routes."