"We know that oil revenue is no longer the lead source of their [the Islamic State's] income in dollars. So, they are changing," Kirby said.
Kirby admitted that he was unsure was no longer the top IS revenue source, but that donations and the group's "black market program" were likely new ways the terrorist organizations was relying on funding.
While the US-led international coalition of over 60 continues conducted 14 airstrikes against IS in Syria and Iraq on Monday and Tuesday, in recent days the group has also released video footage of them executing hostages from Jordan and Japan.
Jordanian Hostage Murder May Backfire on Islamic State
The Islamic State (IS) decision to murder Jordanian pilot Muath al-Kasaesbeh by setting him on fire will eventually be a setback for the terrorist organization, the Pentagon Press Secretary John Kirby said.
“I do think that this will be a setback eventually,” Kirby said on Tuesday. “Regionally it will backfire on them.”
“I think that they believe that there is propaganda value in not only doing this, but videotaping it and posting it online,” Kirby said.
On Tuesday, the IS released a video purporting to show al-Kasaesbeh being burned alive in a cage. The IS took him hostage in December when al-Kasaesbeh’s plane crashed in northern Syria.
Jordan had threatened to execute all al-Qaeda prisoners it holds if al-Kasaesbeh was harmed.
The IS Sunni extremist group began fighting the Syrian government in 2012, later expanded to Iraq. The militant group controls large portions of land in both countries and declared a caliphate on the areas it controls. The Taliban, which increased its activities in 2014, also intends to establish an Islamic state in Afghanistan.