Trump wants Iran’s uranium. Tehran buried it behind collapsed tunnels and mines: Report

As the United States and Iran edge closer to an agreement aimed at ending months of conflict, a new obstacle has emerged: Tehran has reportedly fortified the sites believed to contain its stockpile of near bomb-grade uranium, potentially complicating one of the deal’s most sensitive provisions.

CNN, citing five sources familiar with US intelligence, reported that Iran has deliberately collapsed tunnels housing much of its highly enriched uranium stockpile and planted explosive mines around entrances, making access significantly more difficult and dangerous.

Uranium retrieval becomes more complicated

The stockpile in question consists of roughly half a tonne of highly enriched uranium (HEU), material that experts say is close to weapons-grade.

According to the CNN report, much of the uranium is believed to be buried within collapsed tunnels at the Isfahan nuclear complex in central Iran, with additional quantities stored at other sites.

The reported fortifications mean that retrieving the material would now require extensive excavation and de-mining operations.

Even for Iran itself, accessing the stockpile could prove difficult.

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“It would definitely complicate retrieving the HEU,” Scott Roecker, who headed the US National Nuclear Security Administration’s Office of Nuclear Material Removal between 2017 and 2021, told CNN.

Key test for emerging US-Iran deal

The issue has assumed added significance because the fate of Iran’s enriched uranium is emerging as one of the central elements of a proposed agreement between Washington and Tehran.

A senior US administration official told reporters on Friday that both sides had broadly agreed on a framework under which Iran would surrender its enriched uranium stockpile to the United States. The material would be destroyed on site before being removed from the country, the official said.

However, competing accounts from US and Iranian officials have cast doubt over the exact terms of the agreement.

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Iranian officials have indicated they prefer diluting the uranium rather than relinquishing it entirely, while Tehran has maintained that its nuclear programme is peaceful.

Could Iran retain some of its stockpile?

The newly fortified sites have also raised concerns among nuclear experts that verifying Iranian compliance could become more complicated.

Roecker warned that if Iran is tasked with producing its full inventory of enriched uranium, Tehran could potentially argue that some of the material is no longer retrievable.

“In this scenario, I would worry that Iran would claim that some portion of the HEU was irretrievable,” he told CNN.

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“We wouldn’t have full confidence that Iran couldn’t retain access to it at some point in the future.”

Such uncertainties could complicate future inspections and prolong technical negotiations even if a broader political agreement is reached.

Trump had previously considered a military operation

US President Donald Trump has repeatedly described securing Iran’s enriched uranium as a priority in negotiations aimed at ending the conflict and reopening the Strait of Hormuz.

CNN previously reported that US military planners had prepared options earlier this year to seize the stockpile by force. However, the operation was ultimately considered too risky.

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Trump himself acknowledged the challenges of recovering the material through military means.

“We know exactly what’s happening,” Trump told Fox News in May.

“Nobody’s even gotten close to it.”

Booby-trapped

Inside Isfahan

The loophole

Hormuz factor

Getting it out

01 / 05

The fortification

Tunnels collapsed, entrances mined

Iran has deliberately collapsed tunnels housing much of its highly enriched uranium and planted explosive mines around the entrances, CNN reported, citing five people familiar with US intelligence. Retrieving the material would now demand extensive excavation and de-mining — even for Iran itself.

Tunnels deliberately collapsed

Much of the stockpile is now buried inside caved-in tunnels.

Explosive mines at entrances

Access is now significantly more difficult and dangerous.

Excavation and de-mining required

Recovery becomes a slow, hazardous physical operation.

"It would definitely complicate retrieving the HEU."

— Scott Roecker, former head of the US NNSA Office of Nuclear Material Removal (2017-2021), to CNN

02 / 05

The location

Buried at the Isfahan complex

Much of the uranium is believed to be buried within collapsed tunnels at the Isfahan nuclear complex in central Iran, with additional quantities stored at other sites. Experts describe the material as close to weapons-grade.

≈ ½ tonne

Highly enriched uranium (HEU) at the centre of the deal — described as close to weapons-grade

Isfahan, central Iran

Believed to hold the bulk of the buried stockpile.

Spread across multiple sites

Additional quantities are held elsewhere, the report says.

03 / 05

Verification risk

An "irretrievable" escape hatch

The fortified sites have raised concern that verifying Iranian compliance could become harder. If Tehran is asked to produce its full inventory, it could argue that some material is no longer recoverable — leaving inspectors unable to confirm Iran has surrendered everything.

Compliance hard to verify

No full confidence Iran could not regain access later.

Talks likely to drag

Technical negotiations could be prolonged even after a political deal.

"I would worry that Iran would claim that some portion of the HEU was irretrievable."

— Scott Roecker, former NNSA official, to CNN

04 / 05

The stakes

Why the Strait of Hormuz is in the deal

The emerging agreement aims to reopen the Strait of Hormuz and halt hostilities, and could be signed within days. The conflict has disrupted global shipping and heightened tensions across the Gulf — making the Strait a central prize of any settlement.

Strait reopening tied to the deal

A core aim of the proposed US-Iran framework.

Global shipping disrupted

Months of conflict have squeezed one of the world's busiest sea lanes.

Gulf tensions heightened

A signed deal is being viewed as a potential turning point.

05 / 05

The removal

How you move half a tonne of HEU

Under the broad framework, the material would be destroyed on-site before being removed from Iran. Even if a deal is signed within days, experts caution the operation could take weeks and require specialised US teams and mobile uranium-processing capability.

2 wks+

Trump's estimate for the removal operation alone

2

Top negotiators — Witkoff and Kushner — who reportedly visited Oak Ridge this month

Specialised NNSA teams

Drawn from the US National Nuclear Security Administration.

Oak Ridge, Tennessee

Mobile uranium-processing capability associated with the lab.

Destroyed on-site, then removed

The framework's sequence for handling the stockpile.

Sources: CNN (citing five people familiar with US intelligence) · senior US administration official · Scott Roecker, former NNSA official · Donald Trump, Fox News (May)

Technical hurdles remain

Even if Washington and Tehran formally sign an agreement in the coming days, experts caution that removing the uranium could take weeks.

The process would likely require specialised teams from the US National Nuclear Security Administration and mobile uranium-processing capabilities associated with Oak Ridge National Laboratory in Tennessee.

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Top US negotiators Steve Witkoff and Jared Kushner reportedly visited the facility earlier this month.

Trump has previously said the removal operation alone could take at least two weeks.

Why it matters

The emerging deal is being viewed as a potential turning point in a conflict that has disrupted global shipping and heightened tensions across the Gulf. But the reported fortification of Iran’s uranium stockpile underscores how the most difficult phase may still lie ahead.

While diplomats may be close to agreeing on broad principles, translating those commitments into verifiable action on the ground could prove far more complicated.

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For Washington, ensuring that Iran cannot retain access to near-bomb-grade uranium remains a central objective. For Tehran, preserving its sovereignty and avoiding the appearance of surrendering strategic assets remains equally important.

(With inputs from agencies)