The U.S. operation that killed a key ISIS commander on Saturday was a "significant blow" to the terror group, U.S. Defense Secretary Ashton Carter said. ISIS militant Abu Sayyaf - involved the major black market business fueling the group - was killed after he fought capture in the raid at al-Omar in eastern Syria, Carter said. "Abu Sayyaf was involved in ISIL's military operations and helped direct the terrorist organization's illicit oil, gas and financial operations as well," Carter said in the statement, using an alternative acronym for ISIS. He was killed during the course of the operation when he "engaged U.S. forces," Carter added. "The operation represents another significant blow to ISIL, and it is a reminder that the United States will never waver in denying safe haven to terrorists who threaten our citizens, and those of our friends and allies." Carter had ordered the raid against the terror group at the direction of President Barack Obama. ‘Chief Financial Officer of ISIS' Abu Sayyaf was a Tunisian citizen, a senior administration official said in comments to CNN. Speaking to the news network, another U.S. official "with direct knowledge of the intelligence and the ground operation" described Abu Sayyaf as "Chief Financial Officer of all of ISIS with expertise in oil and gas" who had an increasing role in operations, planning and communications. Communications elements, such as computers, were seized in the raid. "We now have reams of data on how ISIS operates, communicates and earns its money," the official told CNN. Abu Sayyaf's wife was also captured and is in a U.S. military detention in Iraq after what has become the first publicly declared Special Forces operation by U.S. forces in Syria since their failed attempt to rescue American journalist James Foley and other American hostages held by ISIS last summer. Foley was killed by the ultra-radical group, an offshoot of al-Qaeda. U.S. officials suspect Abu Sayyaf's wife "played an important role in ISIS's terrorist activities, and may have been complicit in the enslavement of the young woman rescued last night," the White House said.
