WASHINGTON – US intelligence assessments indicate that the time Iran would need to build a nuclear weapon has not changed since last summer, when analysts estimated that a US-Israeli attack had pushed back the timeline to up to a year, according to three sources familiar with the matter. The assessments of Tehran’s nuclear program remain broadly unchanged even after two months of war that US President Donald Trump launched in tandem with Israel.
The latest US and Israeli attacks that began on February 28 have resulted in many civilian deaths, but Israel has claimed to have hit several significant nuclear facilities. The war has ceased since the US and Iran agreed to a truce on April 7 to pursue peace. Tensions remain high as both sides appear deeply divided, and as Iran has choked traffic through the Strait of Hormuz.
The Nuclear Timeline
Secretary of Defence Pete Hegseth has said publicly that the US aims to ensure Iran does not obtain a nuclear weapon via ongoing negotiations with Tehran. US intelligence agencies had claimed before June’s 12-day war that Iran likely could produce enough bomb-grade uranium for a weapon and build a bomb in around three to six months, said two of the sources, all of whom requested anonymity to discuss US intelligence.
Following the June strikes by the US that hit the Natanz, Fordow and Isfahan nuclear complexes, US intelligence estimates pushed that timeline back to about nine months to a year, said the two sources and a person familiar with the assessments.
Damage to Nuclear Facilities
The attacks destroyed or badly damaged the three enrichment plants known to have been operating at the time. But the UN nuclear watchdog has been unable to verify the whereabouts of some 440 kilograms of uranium enriched to 60%. It believes that about half was stored in an underground tunnel complex at the Isfahan Nuclear Research Centre, but it has been unable to confirm that since inspections were suspended.
The International Atomic Energy Agency assesses that the total HEU stockpile would be enough for 10 bombs if further enriched.
White House Response
“While Operation Midnight Hammer obliterated Iran’s nuclear facilities, Operation Epic Fury built on this success by decimating Iran’s defence industrial base that they once leveraged as a protective shield around their pursuit of a nuclear weapon,” said White House spokeswoman Olivia Wales, referring to the June operation and the latest war that began in February.
“President Trump has long been clear that Iran can never have a nuclear weapon – and he does not bluff.”
Focus of the Campaign
The unchanging estimate of how long it would take Iran to build such a weapon reflects in part the focus of the latest US and Israeli military campaign, the sources said. While Israel has struck nuclear-related targets, including a uranium-processing facility in late March, US attacks have concentrated on civilian infrastructure, assassinating Iranian leadership and attempting to destroy its military-industrial base, among other conventional military targets.
The unchanged estimates may also stem from a lack of major nuclear targets that can be readily and safely destroyed following June’s military action, according to some analysts.
Expert Analysis
Eric Brewer, a former senior US intelligence analyst who led assessments of Iran’s nuclear program, said it was not surprising that the assessments have not changed because recent US strikes have not prioritised nuclear-related targets.
“Iran still possesses all of its nuclear material, as far as we know,” said Brewer, vice president of the nuclear materials study program at the Nuclear Threat Initiative arms control think tank. “That material is probably located in deeply buried underground sites where US munitions can’t penetrate.”
Possible Ground Raids
In recent weeks, US officials have contemplated operations which would significantly impede Iran’s nuclear enrichment efforts. Those options include ground raids to retrieve the HEU believed to be stored in the tunnel complex at the Isfahan site.
Iran has repeatedly denied seeking nuclear weapons. US intelligence agencies and the IAEA say Tehran halted a warhead development effort in 2003, though Israel claims that it “secretly” preserved key parts of the program.
Impact of Scientist Killings
Precisely evaluating Iran’s nuclear capacity is difficult, even for the world’s leading intelligence services, say experts. Several US intelligence agencies have independently studied Iran’s nuclear program, and while the sources described a broad consensus regarding Iran’s capacity to build a nuclear weapon, outlier assessments do occur.
Some officials, including US Secretary of State Marco Rubio, have argued that US strikes on Iranian air defences have reduced the nuclear threat by diminishing Iran’s ability to defend its nuclear sites should it decide to rush toward weaponisation in the future.
There is also the impact of Israel’s assassinations of Iran’s leading nuclear scientists. David Albright, a former UN nuclear inspector who runs the Institute for Science and International Security, said the killings have added significant uncertainty to Tehran’s ability to build a bomb that would function as intended.
“I think everyone agrees knowledge can’t be bombed, but know-how certainly can be destroyed,” he said.
Analysis: A Stalemate on the Nuclear Front
The unchanged US intelligence assessments reveal a critical reality: despite two months of war and significant military operations, Iran’s nuclear program remains largely intact. The timeline for Tehran to build a weapon — estimated at nine months to a year — has not shifted since last summer.
The reasons are twofold. First, the most recent US and Israeli strikes have focused on conventional military targets, civilian infrastructure, and leadership assassinations, not on Iran’s deeply buried nuclear facilities. Second, the most valuable nuclear material is believed to be stored in underground complexes that US munitions cannot penetrate.
The prospect of ground raids to retrieve highly enriched uranium would be a significant escalation, carrying immense risks. The US has not yet taken that step.
The assassinations of Iranian nuclear scientists have added uncertainty, but as Albright noted, “knowledge can’t be bombed.” The know-how to build a weapon remains.
As negotiations continue — with Iran having submitted a 14-point proposal and set a one-month deadline — the nuclear issue remains central. The US insists Iran must never obtain a weapon. Iran insists on its right to enrich uranium.
The unchanged intelligence assessments mean that the nuclear clock is still ticking.
