Face the Nation moderator Margaret Brennan previews upcoming interview with Rafael Grossi

WASHINGTON (CBS, KYMA) - Face the Nation host Margaret Brennan interviewed Rafael Grossi, the head of the International Atomic Energy Agency (IAEA), who was in Washington to meet with Trump administration officials Thursday.

This is his first U.S. network interview since the start of the Iran War as questions mount about the security of some of Iran's nuclear facilities and its highly enriched materials.

According to Brennan, National Intelligence Director Tulsi Gabbard told Congress Wednesday that Iran's enrichment program was destroyed.

Gabbard also told Congress that the U.S. has seen no efforts for Iran to try and rebuild their enrichment capability, prompting her to ask Grossi if he agrees with Gabbard's assessment, and if he has any indiction the new supreme leader would want a weapons program, to which he said:

"I don't disagree with that. We don't see major activity, which is logical, because there is a, there is a military campaign ongoing, whatever you're not going to start, you know, bringing cranes and workers...What we have is satellite imagery, all right, so at least the IAEA, maybe others have other technical means or personal means to check what is happening. As far as we are concerned, we haven't seen activity. But as I was saying, a lot still has survived. Not they have the capabilities, they have the knowledge, they have the industrial ability to do that. This is why we need to go back to a negotiating table. It's going to be needed."

You can watch more of Brennan's interview with Grossi on Face the Nation Sunday on CBS at 8:30 a.m. Pacific. You can also watch the full interview HERE.

Brennan also talked about her upcoming interview on CBS Evening News with host Tony Dokoupil.