(CNN) U.S. special operations forces killed a key ISIS commander during a raid in eastern Syria overnight Friday to Saturday -- securing intelligence on how the terror organization operates, communicates and earns money, U.S. government officials said.

The ISIS commander, identified by his nom de guerre Abu Sayyaf, was killed in a heavy firefight after he resisted capture in the raid at al-Omar, U.S. Defense Secretary Ash Carter said in a statement.

The officials identified Sayyaf's captured wife as Umm Sayyaf, an Iraqi. She is now being held in Iraq.

The U.S. government did not release Sayyaf's real name, but Hisham Alhashimi, an Iraqi writer and researcher specializing in ISIS and other security threats, identified one possibility as Nabil Saddiq Abu Saleh al-Jabouri, a close associate of chief ISIS spokesman Abu Mohammed al-Adnani. Iraqi officials could not be immediately reached to confirm or deny Alhashimi's claim.

The ground operation was led by the Army's Delta Force, sources familiar with the mission told CNN. There were about two dozen members of Delta Force involved, sources said.

Delta Force entered the target area on Black Hawk helicopters and V-22 aircraft, a U.S. official familiar with the operation said. ISIS fighters defended the multistory building from inside and outside positions.

Abu Sayyaf was killed as he "tried to engage" U.S. troops, the official said.

Carter said he had ordered the raid at the direction of President Barack Obama. All the U.S. troops involved returned safely.

National Security Council spokeswoman Bernadette Meehan said Obama had authorized the raid "upon the unanimous recommendation of his national security team" and as soon as the United States was confident all the pieces were in place for the operation to succeed.

"Abu Sayyaf was a senior ISIL leader who, among other things, had a senior role in overseeing ISIL's illicit oil and gas operations -- a key source of revenue that enables the terrorist organization to carry out their brutal tactics and oppress thousands of innocent civilians," she said in a statement. "He was also involved with the group's military operations."

(ISIL, or the Islamic State of Iraq and the Levant, is an alternative acronym for ISIS. The Levant is a region west of Iraq that includes Syria.)

Abu Sayyaf was a Tunisian citizen, a senior administration official said.

A U.S. official with direct knowledge of the intelligence and the ground operation said Sayyaf had expertise in oil and gas and had taken an increased role in ISIS operations, planning and communications.

"We now have reams of data on how ISIS operates, communicates and earns its money," the official told CNN, referring to some of the communications elements, such as computers, seized in the raid.

A young woman from the Yazidi religious minority was rescued

"We suspect that Umm Sayyaf is a member of ISIL, played an important role in ISIL's terrorist activities, and may have been complicit in the enslavement of the young woman rescued last night," said Meehan.

Meehan said Umm Sayyaf was being debriefed about ISIS operations, including any information she may have on hostages held by the terror group.

Abu Sayyaf and his wife were suspected to be involved in or have deep knowledge of ISIS hostage operations, a U.S. official with knowledge of the operation told CNN. A team from the FBI-led High Value Interrogation Group is expected to interrogate the wife, the source said. They will seek to find out what she may know about the capture, movement and treatment of hostages.

But Michael Weiss, author of "ISIS: Inside the Army of Terror," said Abu Sayyaf was largely unknown to close observers of the organization.

Weiss said he's skeptical the United States would risk lives to capture the head of ISIS' oil operations. ISIS hasn't made significant money from captured oil fields since U.S. bombers began striking its infrastructure, he said.

A Pentagon spokesman confirmed in February that oil is no longer a main source of revenue for ISIS.

But risking American lives to capture Abu Sayyaf makes sense to Derek Harvey, a former U.S. Army colonel, intelligence officer and the director of the University of South Florida's Global Initiative for Civil Society and Conflict.

"The most important thing about the raid is not getting Abu Sayyaf; it's getting his records," Harvey said.

Harvey said Sayyaf was one of ISIS' top financiers, with likely access to the group's contacts with banks, donors, and Turkish and Lebanese business interests, and links to criminal and smuggling networks.

Harvey said Sayyaf had undeniable value as a target because ISIS is also a business.

"They're meticulous record-keepers," he said.

Meehan's statement added that Obama is "grateful to the brave U.S. personnel who carried out this complex mission as well as the Iraqi authorities for their support of the operation and for the use of their facilities, which contributed to its success."

Meehan said the U.S. did not coordinate with nor advise Syria in advance of the operation.

"We have warned the Assad regime not to interfere with our ongoing efforts against ISIL inside of Syria," she said, adding that the "brutal actions of the regime have aided and abetted the rise of ISIL and other extremists in Syria."