Mojtaba Khamenei chosen as Iran's next supreme leader, Iranian state media reports

"The evidence in front of us since the 12-day war was that Iran had no intention of actually negotiating a nuclear deal that truly meant they did not have a pathway to the nuclear bomb," Defense Secretary Hegseth said at the Pentagon briefing.

Hegseth said that negotiators Jared Kushner and Steve Witkoff "poured into that negotiation, giving them every single possible opportunity to release that that ambition, and they didn't. And the intelligence that we saw [showed] they didn't intend to do it in good faith – that they had the intentions eventually to get to a place where they could have that a conventional shield to block their nuclear capabilities.”

-ABC News Steve Beynon

The Israel Defense Forces said its fighter jets targeted and dismantled the Iranian regime's defense and detection systems at the Mehrabad International Airport in the capital of Tehran.

At a briefing at the Pentagon on Wednesday, Defense Secretary Pete Hegseth said "this is not a 'mission accomplished' situation," instead calling it "a reality check."

Hegseth said that now that both Israel and the U.S. have achieved dominance over the skies of Iran, those operations will be ramped up, shifting from mainly missile strikes in the first days to bomb drops.

“Flying over Tehran, flying over Iran, flying over their capital, flying over the IRGC, Iranian leaders looking up and seeing only us and Israeli air power every minute of every day, until we decide it's over and Iran will be able to do nothing about it,” he said.

“More bombers and more fighters are arriving just today, and now with complete control of the skies, we will be using 500-pound, 1,000-pound and 2,000-pound GPS and laser-guided precision gravity bombs, of which we have a nearly unlimited stockpile," Hegseth said.

“The terms of this war will be set by us at every step,” he said.

Hegseth said additional forces are arriving in the Middle East on Wednesday. CENTCOM on Tuesday night announced 50,000 troops are in the region.

“More and larger waves are coming, we are just getting started," he said.

-ABC News' Luis Martinez

Defense Secretary Pete Hegseth said at a briefing at the Pentagon on Wednesday, "America is winning decisively, devastatingly and without mercy."

“We have only just begun," he said.

"It’s very early and has President Trump has said we will take all the time we need to make sure that we succeed," he said. “We are only four days into this and the results have been incredible."

"We are accelerating, not decelerating," he said.

In a few days, Hegseth said, there will be complete control of Iranian airspace.