Secrets on Iran nuclear strike spill into open as Pentagon defends bombing

The Pentagon on Thursday released an extraordinary number of details about the military’s top-secret bombing of Iran’s nuclear facilities and its defense of an air base in Qatar.

The unusual disclosures – including analysts briefed at secret locations, bombs dropped into ventilation shafts, and a small group of young service members left behind at a base to shoot down Iranian missiles – is being orchestrated by a White House angry over questions about the effectiveness of the U.S. strike, which targeted three Iranian nuclear targets on June 21.

Trump insists Iran’s nuclear program has been “obliterated,” while an early military intelligence assessment said the strike might only have set back Iran’s program by “months.” Military officials say they need much more time to assess the damage.

Here’s what we’ve learned:

There was a 15-year, top-secret mission to figure out how to destroy Iran’s Fordo nuclear facility

In 2009, a U.S. officer working for the Defense Threat Reduction Agency was brought into a vault at an undisclosed location and shown highly classified photos of a construction site in the Iranian mountains, according to Gen. Dan Caine, chairman of the Joint Chiefs of Staff.

Caine said the officer and another colleague would go on to spend 15 years studying the site. They analyzed the weather and the geology of the mountain, along with any items discarded from the site. They eyed ventilation shafts, electrical systems and environmental control systems too, he said.

“Every nook, every crater, every piece of equipment going in and every piece of equipment going out — they literally dreamed about this target at night when they slept,” Caine said.

When the analysts realized they did not have a weapon to strike Fordo if needed, Caine said they teamed up with industry in a top-secret effort to build the Massive Ordnance Penetrator, or GBU-57, specifically to hit it.

“Then, on a day in June of 2025, more than 15 years after they started their life’s work, the phone rang and the president of the United States ordered the B-2 force” to strike the target, Caine said.

One of them later told Caine, “I can’t even get my head around this.”

12 bombs were dropped down two ventilation shafts capped with concrete.

In a bid to defend the strikes as successful, both Secretary of State Marco Rubio and Defense Secretary Pete Hegseth in recent days have publicly disclosed that 12 of the 14 Massive Ordnance Penetrators used in the June 21 strike were dropped on the nuclear facility at Fordo.

At the briefing on Thursday, Caine went further, describing that six bunker-buster bombs were dropped down each of the two ventilation shafts with fuses programmed to detonate at specific times.

Caine said the Iranians had covered the ventilation shafts with concrete caps, but the first bomb blew off the caps. After that, the next four bombs were programmed to drop more than 1,000 feet per second and “explode in the mission space.” The final bomb was designated as a “flex weapon,” or backup, he said.

“All six weapons at each vent, at Fordow went exactly where they were intended to go,” Caine said, adding that the result was “a mix of overpressure and blast ripping through the open tunnels and destroying critical hardware.”

Caine said the fighter pilots who trailed the B-2 bombers said that after the first bomb struck the target “the pilots stated, quote, this was the brightest explosion that I’ve ever seen. It literally looked like daylight.”

DIA says Fordo damaged, but questions remain on impact to Iran’s nuclear program.

About a day after the attack, the Defense Intelligence Agency produced an early assessment estimating Iran’s nuclear program was set back by “months.”

According to the two people familiar with the classified report, the bombing sealed off the entrances to two of the three nuclear sites targeted in the attack but that most of the damage was done to structures above ground, leaving the lower structures intact. The assessment also found that at least some enriched uranium remained – possibly moved from the nuclear sites ahead of the blasts.

President Donald Trump insists the enriched uranium wasn’t moved in advance.

Hegseth, visibly angry that details of the report had leaked, said “new intelligence” estimates the Iran program has been knocked back by “years,” not months, and he read from the classified assessment to reporters.

“It points out that it’s not been coordinated with the intelligence community at all,” said Hegseth, adding that the report was labeled “low confidence.”

A couple of dozen service members in their 20s defended a U.S. airbase in Qatar.

Two days after the strike, U.S. officials got word that Iran was planning to launch a retaliatory attack on an American air base in Qatar called al-Udeid.

According to Caine, officials quickly evacuated the base in part of extend the security perimeter, leaving behind two Patriot missile batteries and some 44 soldiers.

Of the troops left to defend the base, the oldest was a 28-year-old captain.

Caine said the group listened to “chatter” of the impending attack in the oppressive heat and were told to ensure their missile batteries were pointed north. Iran began launching short- and medium-range missiles, prompting the soldiers to unleash “round after round” of Patriot missiles from their canisters.

Caine called the operation the “largest single Patriot engagement in U.S. military history,” noting the Qataris aided in the defense.

“I’m not going to tell you how many rounds were shot,” Caine said, noting the number was classified. “But it was a bunch.”

ABC News’ Chris Boccia contributed to this report.