Did the US destroy Fordow or just delay Iran's nuclear programme?

Commercial satellite imagery indicates the US attack on Iran's Fordow nuclear facility severely damaged - and possibly destroyed - the deeply-buried site and the uranium-enriching centrifuges it housed, but there was no confirmation, experts said on Sunday.

"They just punched through with these MOPs," said David Albright, a former UN nuclear inspector who heads the Institute for Science and International Security, referring to the Massive Ordnance Penetrator bunker-busting bombs that the US said it dropped. "I would expect that the facility is probably toast."

Following the strike on Sunday, US President Donald Trump declared that the site had been "completely and totally obliterated" and demanded Iran return to negotiations.

But confirmation of the below-ground destruction could not be determined, noted Decker Eveleth, an associate researcher with the CNA Corporation who specialises in satellite imagery.

The hall containing hundreds of centrifuges is "too deeply buried for us to evaluate the level of damage based on satellite imagery," he told Reuters.

To defend against attacks such as the one conducted by US forces early on Sunday, Iran buried much of its nuclear programme in fortified sites deep underground, including, in Fordow's case, into the side of a mountain.

Satellite images show six holes where the bunker-busting bombs appear to have penetrated the mountain, and the ground looks disturbed and covered in dust.

The head of the UN International Atomic Energy Agency (IAEA) said on Monday that while the facility likely suffered "very significant damage", it is currently impossible to quantify.

"At this time, no one - including the IAEA - is in a position to have fully assessed the underground damage at Fordow," Rafael Grossi told an emergency board meeting.

Iranian officials have downplayed the extent of the destruction. A lawmaker representing Qom, near Fordow, claimed that the damage was "quite superficial" and limited mostly to structures at ground level.

The US and Israel have said they intend to halt Tehran's nuclear programme. But a failure to destroy its facilities, equipment and uranium stockpile could leave Iran able to easily restart the weapons programme that US intelligence and the IAEA say it shuttered in 2003.

'Unusual activity'

Several experts also cautioned that Iran likely moved a stockpile of near weapons-grade highly enriched uranium out of Fordow before the strike early on Sunday morning and could be hiding it and other nuclear components in locations unknown to Israel, the US and UN nuclear inspectors.

They noted satellite imagery from Maxar Technologies showing "unusual activity" at Fordow on Thursday and Friday, with a long line of vehicles waiting outside an entrance of the facility. A senior Iranian source told Reuters on Sunday that most of the highly enriched uranium had been moved to an undisclosed location before the US attack.

US Vice President JD Vance on Sunday appeared to cast doubt over whether the nuclear material was destroyed in the strikes.

"We are going to work in the coming weeks to ensure that we do something with that fuel, and that's one of the things that we’re going to have conversations with the Iranians about," he told ABC News.

Iran is thought to have stockpiled more than 400 kg of uranium enriched to 60 percent, just shy of the 90 percent required to produce weapons-grade nuclear material and enough for around 10 warheads.

"I don't think you can with great confidence do anything but set back their nuclear program by maybe a few years," said Jeffrey Lewis of the Middlebury Institute of International Studies at Monterey. "There's almost certainly facilities that we don't know about."

Arizona Sen. Mark Kelly, a Democrat and member of the Senate intelligence committee who said he had been reviewing intelligence every day, expressed the same concern.

"My big fear right now is that they take this entire program underground, not physically underground, but under the radar," he told NBC News. "Where we tried to stop it, there is a possibility that this could accelerate it."

Iran has long insisted that its nuclear program is for peaceful purposes. But in response to Israel's attacks, Iran's parliament is threatening to withdraw from the Non-Proliferation Treaty, the cornerstone of the international system that went into force in 1970 to stop the spread of nuclear weapons, ending cooperation with the IAEA.

"The world is going to be in the dark about what Iran may be doing," said Daryl Kimball, executive director of the Arms Control Association advocacy group.

'Double tap'

Reuters spoke to four experts who reviewed Maxar Technologies' satellite imagery of Fordo,w showing six neatly spaced holes in two groups in the mountain ridge beneath which the hall containing the centrifuges is believed to be located.

General Dan Caine, chairman of the US Joint Chiefs of Staff, told reporters that seven B-2 bombers dropped 14 GBU-57/B MOPs, 30,000-pound precision-guided bombs designed to drive up to 200 feet into hardened underground facilities like Fordow, according to a 2012 congressional report.

Caine said initial assessments indicated that the sites suffered extremely severe damage, but declined to speculate about whether any nuclear facilities remained intact.

Eveleth said the Maxar imagery of Fordow and Caine's comments indicated that the B-2s dropped an initial load of six MOPs on Fordow, followed by a "double tap" of six more in the exact same spots.

Operation Midnight Hammer also targeted Tehran’s main uranium enrichment facility at Natanz, he said, and struck in Isfahan, the location of the country's largest nuclear research centre. There are other nuclear-related sites near the city.

Israel had already struck Natanz and the Isfahan Nuclear Research Centre in its 10-day war with Iran.

Albright said in a post on X that Airbus Defence and Space satellite imagery showed that US Tomahawk cruise missiles severely damaged a uranium facility at Isfahan and an impact hole above the underground enrichment halls at Natanz reportedly caused by a Massive Ordnance Penetrator bunker-busting bomb that "likely destroyed the facility."

Albright questioned the US use of cruise missiles in Isfahan, saying that those weapons could not penetrate a tunnel complex near the main nuclear research centre believed to be even deeper than Fordow. The IAEA said the tunnel entrances "were impacted."

He noted that Iran recently informed the IAEA that it planned to install a new uranium enrichment plant in Isfahan.

"There may be 2,000 to 3,000 more centrifuges that were slated to go into this new enrichment plant," he said. "Where are they?"

(Reuters and TNA staff)