In a rare ground attack deep into Syria, U.S. Army commandos killed a man described as the Islamic State’s head of oil operations, captured his wife and rescued a woman whom American officials said was enslaved.

A team of Delta Force commandos slipped across the border from Iraq under cover of darkness Saturday aboard Black Hawk helicopters and V-22 Osprey aircraft, according to a U.S. defense official knowledgeable about details of the raid. The official was not authorized to discuss the operation publicly and spoke on condition of anonymity.

The Americans intended to capture a militant identified by U.S. officials as Abu Sayyaf. When they arrived at his location, a multi-story building, they met stiff resistance, the U.S. official said, and a firefight ensued, resulting in bullet-hole damage to the U.S. aircraft.

Abu Sayyaf was killed, along with an estimated dozen IS fighters, U.S. officials said. No American was killed or wounded.

The United States is leading a coalition in a military campaign to roll back the jihadist group whose self-declared caliphate in Syria and Iraq has reshaped the region.

Conducted by U.S. personnel based out of Iraq, the raid targeted an area called al-Amr in eastern Syria, an Islamic State stronghold that bridges territory the group controls in Syria and Iraq.

Report compiled with information from Associated Press and Reuters.