A satellite photo in June by Maxar Technologies, shows craters and ash on the ridge at the Fordow underground complex in Iran after US strikes. Photo / Maxar Technologies
Iran’s deeply buried nuclear enrichment plant at Fordow was badly damaged, and potentially destroyed, by the 12 massive bombs that United States Air Force B-2 bombers dropped on it last month, according to a new American intelligence assessment.
Two other nuclear sites targeted in the US attacks were not as badly damaged, but facilities at the sites that would be key to fabricating a nuclear weapon were destroyed and could take years to rebuild, US officials said.
A senior Israeli official said last week that the strikes most likely did not eliminate the stockpile of near-bomb-grade fuel that could be used to produce upward of 10 nuclear weapons. But without the facilities to manufacture a weapon, US officials insist, the fuel would be of little use even if the Iranians can dig it out of the rubble.
The new assessment helps create a clearer picture of what the combined Israeli and US strikes on Iran achieved.
The bombings deeply damaged Fordow — considered by the Iranians to be their best-protected and most advanced nuclear enrichment site — probably crippling Iran’s ability to make nuclear fuel for years to come.
Iran most likely still has a stockpile of uranium enriched to 60% purity, which is just below the level that is usually used in nuclear weapons, US and Israeli officials say.
But the officials believe it is buried under rubble, and Israeli officials believe that only the stockpile at Iran’s nuclear laboratory at Isfahan is accessible despite the strikes on it.
The crucial question of how long the American strikes have set back either the overall Iranian nuclear programme or Iran’s ability to use its existing uranium to make a crude bomb continues to be debated within the US Government.
The new US assessment was earlier reported by NBC News.
The main target of the American bombing was Fordow, which was hit by a dozen GBU-57 bunker-busting bombs. The assessment concludes those explosions wiped out the thousands of delicate nuclear centrifuges buried under the mountain, a finding consistent with statements by the head of the International Atomic Energy Agency.
Multiple US officials said it would take at least two years of intensive work before the Fordow facility could be operational again. Other experts say that if Iran seeks to restart its programme, it is likely to do so at other underground sites.
In addition to Fordow and Isfahan, the US Air Force dropped two bombs on Iran’s older enrichment plant at Natanz, which had facilities above and below ground. A US Navy submarine fired cruise missiles at Isfahan, trying to destroy above-ground facilities there.
While the underground facilities at Natanz and tunnels at Isfahan were far less damaged, US officials said that any effort by Iran to repair or gain access to them could be detected.
Rebuilding the conversion facilities would also probably be spotted.
With much of Iran’s air defences destroyed, Israeli or US forces could attack again, stopping any reconstruction efforts, US officials said.
An Israeli official repeated last week that the country was prepared to “mow the lawn”, suggesting sites could be reattacked.
While US President Donald Trump has declared that all three sites were “obliterated” and that Iran has given up its nuclear ambitions, US officials do not yet know whether the country is determined to restart the effort, nor whether it will try to move towards a bomb with whatever enriched uranium that remains.
Trump and Israeli officials say their willingness to strike again may deter the Iranians from even trying.
In the strikes at Fordow, the United States sent some of the bunker-busters down air ventilation shafts that took them closer to the buried control room and the centrifuge halls.
That avoided having to blast through hundreds of yards of rock. Even if the bombs did not reach the centrifuge halls, US and Israeli officials say, the blast wave would have wiped out the centrifuges, including some of Iran’s most advanced and efficient models.
In contrast, Natanz was struck by only two of the Massive Ordnance Penetrators. Those strikes left much of the facility intact, though they probably destroyed the centrifuges and cut off Iran’s ability to reach specific parts of the facility.
Military planners in US Central Command had proposed multiple plans to the White House that would have utilised multiple waves of strikes against the sites that could have potentially done more damage.
Current and former military officials had cautioned before the strike that any effort to destroy the Fordo facility, which is buried more than 75m under a mountain, would probably require waves of airstrikes, with days or even weeks of pounding the same spots.
But Trump decided on a more limited single strike on the three sites and then pushed Israel to end its war against Iran.
After the strikes, the Defence Intelligence Agency conducted an early assessment that said the Iranian nuclear programme had been set back by only a few months. But soon afterwards, John Ratcliffe, the CIA director, announced that “a body of credible intelligence” indicated the nuclear programme had been severely damaged.
“Several key Iranian nuclear facilities were destroyed and would have to be rebuilt over the course of years,” Ratcliffe wrote.
Ratcliffe’s comments reflected growing confidence by US officials that Fordow’s nuclear facilities were badly damaged and that the facility at Natanz that was meant to convert uranium into a metal that could be used in weapon was also destroyed.
Ratcliffe delivered a more detailed report to lawmakers, saying it would take years to rebuild the metal conversion facility.
Sean Parnell, the chief Pentagon spokesperson, said in a statement that it would take “years to recover” Iran’s nuclear facilities, and reiterated Trump’s announcement that Iran’s facilities were “obliterated”.
“There is no doubt about that,” Parnell said. “Operation Midnight Hammer was a significant blow to Iran’s nuclear capabilities.”
Some experts have criticised the US focus on just the three sites, arguing that Iran has others that it could use to restart the programme.
“We’re too caught up in the stories about the big three sites — Fordow, Natanz and Isfahan — when really Iran’s capabilities are much more sprawling and sophisticated, and include many sites that the US and Israel did not bomb,” said Rosemary Kelanic, an expert with Defence Priorities, a think-tank advocating a restrained foreign policy.
“Focusing too much on the big three sites misses the larger point that even if those three sites and their contents — centrifuges, stockpiles — were destroyed, Iran could likely still rebuild quickly.”
Jeffrey Lewis, a professor at the Middlebury Institute of International Studies who has studied commercial satellite imagery of Iran, said he believed that three underground sites in Iran were not struck, one near Natanz, one at the Parchin military complex and a third secret site.
He was sceptical that the additional sites could be easily struck, despite the US officials’ certainty.
“If it were easy, they would have done it right away,” Lewis said.
This article originally appeared in The New York Times.
Written by: Julian E. Barnes, David E. Sanger and Eric Schmitt
©2025 THE NEW YORK TIMES