SCOTT SIMON, HOST:

The United States has killed a senior leader of the self-proclaimed Islamic State in Syria. Abu Sayyaf's death was confirmed today by Defense Secretary Ash Carter, who says that no U.S. forces were killed or injured during the operation. We're joined now by NPR's Pentagon correspondent, Tom Bowman.

Tom, thanks for being with us.

TOM BOWMAN, BYLINE: You're welcome Scott.

SIMON: And what more can you tell us about this operation?

BOWMAN: Well, I'm told this was undertaken by soldiers from the Army's Delta Force. That's a special operations organization, very secretive and it's akin to the Navy SEAL Team 6 which killed bin Laden. And I'm told that several Chinook helicopters, Black Hawk helicopters, were used in this operation that launched into the town of al-Amr in eastern Syria. And sources tell me it took several hours, that there was a gunfight here at this location. And they estimate that roughly a dozen or so ISIS members were killed in this operation at a residential building. And also Abu Sayyaf's, wife she's an Iraqi named Umm Sayyaf, was captured in the operation and taken to Iraq for interrogation.

SIMON: And how significant a figure was Abu Sayyaf?

BOWMAN: Well, one person I spoke with said he's a medium-to-large figure in the organization. He's not one of the top four including al-Baghdadi that runs the organization. There was no bounty on his head. And clearly he ran the oil operation, which is the most lucrative part of their organization besides, you know, ransoming - kidnapping people and holding them for ransom. So it's a pretty big deal, but if you're an administrative person in an organization like ISIS, you always have a deputy or others involved that could probably take your place. So they'll point to it as a pretty big win, but again, it's not one of the top four in the ISIS organization.

SIMON: Well, it does bring up the question as to, I guess, whether he was specifically targeted or if there's some hope that this death is going to affect ISIS's ability to run their oil operations and generate revenue.

BOWMAN: Well, the biggest problem with their oil operation right now is the U.S. bombing. They've been hitting their installations. They've been hitting convoys of oil trucks, you know, really since last summer now. And clearly that has put a damper on their oil operations. But, you know, again they can still, you know, get money in other ways. So - and they're widely seen as the richest of all the terrorist groups. So something like this, you know, it's going to hurt them a bit. And again, it's more of a public relations win, I would think. But ISIS is still a big organization and it's still, you know, it's still out there fighting.

SIMON: Let's note of course that this raid, which Secretary Carter says has certainly been successful, comes after recent disclosures of the number of raids and rescue attempts that didn't work out so well.

BOWMAN: That's absolutely right. They tried to get some hostages in this part of Syria, tried to get them back. That was not successful. At this point, they're sort of containing ISIS. The big operations in Iraq and Mosul have yet to start. They still have troubles in Syria. They really need a ground force here. They don't really have it right now in Syria. And they have just started training-up moderate Syrian rebels to undertake that ground operation. That'll be the big difference against ISIS when that happens in the coming months or maybe more than a year.

SIMON: And does this underscore, in its own way, this raid, some of the tension in U.S. policy between commitment of special forces now that are carrying the burden of the struggle against ISIS against those voices who are - that are calling for something more aggressive and say boots on the ground are necessary?

BOWMAN: Absolutely. The special operations forces really are the only boots on the ground right now for the U.S. Some have called for a larger U.S. ground force, but the administration at this point has said no.

SIMON: Tom Bowman is NPR's Pentagon correspondent.

Thanks very much for being with us.

BOWMAN: You're welcome, Scott. Transcript provided by NPR, Copyright NPR.