Inside the U.S. raid that killed a key ISIS leader

THE PENTAGON -- In an early morning mission conducted under the cover of darkness Saturday, a team of Delta Force commandos took out roughly a dozen Islamic State of Iraq and Syria fighters, including a key ISIS leader, Abu Sayyaf -- the man described as the head of the terror group's lucrative oil operations.

The commandos went into eastern Syria aboard Black Hawk helicopters and Osprey tilt rotor aircraft. Their target was a building where Sayyaf lived with his wife and oversaw black market oil operations, a major source of ISIS income.

One Pentagon official called Sayyaf the "Chief Financial Officer of ISIS."

Pentagon: U.S. training Syrians to fight ISIS

ISIS oil facilities have been frequent targets of the U.S.-led bombing campaign. This time, the Delta commandos intended to capture the man who ran the operation.

A firefight broke out, and according to Pentagon officials, some of the ISIS fighters attempted to use women and children as human shields. About a dozen enemy fighters were killed in fighting that sometimes involved hand-to-hand combat.

Pentagon officials said there were no reports of civilian casualties and no Americans were killed or wounded, although there were bullet holes in some of the aircraft.

The commandos found Sayyaf and his wife, Umm Sayyaf, on the top floor of the building. According to Pentagon officials, he attempted to resist and was killed.

Tragic end for ISIS hostage Kayla Mueller

His wife was captured and taken back to Iraq, along with a young Iraqi woman who officials believe had been enslaved by Abu Sayyaf.

The young woman will be returned to her family. The wife will be interrogated.

Officials believe she knows about the abuse suffered by Kayla Mueller, the American aid worker who died earlier this year while being held hostage by ISIS.

Defense Secretary Ash Carter called the killing of Abu Sayyaf a significant blow to ISIS, although no one expects it to cripple the organization.

This was the first successful commando raid into Syria. The troops brought back captured cellphones and laptops, which will now used in an effort to track down other ISIS leaders.

  • David Martin

    David Martin is CBS News' National Security Correspondent.