American special operations forces killed a senior Islamic State leader in a raid in Syria, U.S. officials said on Saturday, an operation that appeared to mark a departure from Washington's strategy of relying mostly on a bombing campaign to target militant leaders there.

President Barack Obama ordered the overnight operation that killed Abu Sayyaf, identified as an Islamic State commander who helped manage the group's black-market sales of oil and gas to raise funds, U.S. officials said. His wife, Umm Sayyaf, was captured and was being held in Iraq.

It was the first known U.S. special forces operation inside Syria apart from a failed secret effort to rescue a number of U.S. and other foreign hostages held by Islamic State in northeastern Syria last year.

Wary of the United States getting pulled deeper into Middle East conflicts, Obama has promised not to commit major ground forces in the fight against Islamic State, which has seized swathes of Syria and Iraq. He has left open the prospects of special forces raids, though it was not immediately clear if the latest one marked the start of a new chapter in Syria.

U.S. special forces based in Iraq flew by helicopter on a mission aimed at capturing Abu Sayyaf in al-Amr in eastern Syria, U.S. officials said. One official said the elite Delta Force was used in the mission, and that UH-60 Black Hawk helicopters and V-22 Osprey tiltrotor aircraft were involved.

"Abu Sayyaf was killed during the course of the operation when he engaged U.S. forces," Defense Secretary Ash Carter said.

About a dozen Islamic State fighters were also killed in the raid, two U.S. officials said. One official said enemy forces fired at the U.S. aircraft and there was hand-to-hand combat during the raid.

No U.S. forces were killed or wounded during the operation, Carter said.

"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 said, using an acronym for the Islamic State organization.

The raid in Syria came at a time when Islamic State, which has declared a caliphate in areas it controls and has carried out beheadings and massacres, has scored high-profile gains in Iraq and made advances in Syria.

Islamic State militants raised their black flag over the local government headquarters in the Iraqi city of Ramadi on Friday and claimed victory through mosque loudspeakers after overrunning most of the western provincial capital.

If Ramadi were to fall it would be the first major city seized by the Sunni insurgents in Iraq since security forces and paramilitary groups began pushing them back last year.


Obama gave the go-ahead for Syria raid.

"The president authorized this operation upon the unanimous recommendation of his national security team and as soon as we had developed sufficient intelligence and were confident the mission could be carried out successfully," said White House National Security Council spokeswoman Bernadette Meehan.

Meehan said the operation was conducted "with the full consent of Iraqi authorities." But she said the United States did not give any advance warning or coordinate with the government of Syrian President Bashar al-Assad, who Washington strongly opposes.

The raid followed Obama's Camp David summit earlier this week with Saudi Arabia and other Gulf Arab allies who have long pressed the United States to be more militarily assertive in Syria, especially in support of moderate rebels seeking to oust Assad.

Carter said that U.S. special operations forces conducted the operation targeting Abu Sayyaf and his wife.

Abu Sayyaf "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," Meehan said.

His wife was also suspected of playing "an important role in ISIL's terrorist activities," Meehan said. She said U.S. forces freed a young Yezidi woman "who appears to have been held as a slave by the couple."

U.S. and Arab forces have been carrying out almost daily air raids against hardline Islamist militant groups in Syria including Islamic State since last September, and U.S.-led forces are also targeting the group in Iraq.