Authors: Gram Slattery, Jonathan Landy, and Erin Banko
WASHINGTON (Reuters) – A U.S. intelligence assessment shows that the time it would take for Iran to build a nuclear weapon has not changed since last summer, when analysts estimated that U.S.-Israeli strikes had delayed the timeline by a year, three people familiar with the matter said.
Even as U.S. President Donald Trump launched two months of war, in part to prevent the Islamic Republic from developing a nuclear bomb, assessments of Tehran’s nuclear program have remained largely unchanged.
The latest attacks by the United States and Israel, which began on February 28, mainly targeted conventional military targets, but Israel struck a number of important nuclear facilities.
The unchanged timetable suggests that severely hampering Tehran’s nuclear program may require destroying or clearing Iran’s remaining stockpile of highly enriched uranium (HEU).
The war has stalled since the United States and Iran agreed to a truce on April 7 to seek peace. Tensions remain high as the two sides appear to have deep differences and Iran has blocked traffic in the Strait of Hormuz, cutting off about 20% of the world’s oil supplies and triggering a global energy crisis.
Defense Secretary Pete Hegseth has publicly stated that the United States aims to ensure that Iran does not obtain a nuclear weapon through ongoing negotiations with Tehran.
U.S. intelligence agencies concluded before the 12-day war in June that Iran might be able to produce enough bomb-grade uranium for a weapon and build a bomb in about three to six months, two sources said. They all requested anonymity to discuss U.S. intelligence.
U.S. intelligence agencies estimate the delay to about nine months to a year following U.S. attacks on nuclear facilities in Natanz, Fordow and Isfahan in June, two sources and one person familiar with the matter said.
These attacks destroyed or seriously damaged three enrichment plants known to be operating at the time. But the U.N. nuclear watchdog has been unable to verify the whereabouts of about 440 kilograms of uranium enriched to 60 percent. It believes about half is stored in an underground tunnel complex at the Isfahan Nuclear Research Center, but it cannot confirm this because inspections are suspended.
The International Atomic Energy Agency has assessed that the total stockpile of highly enriched uranium is sufficient to make 10 bombs if further enriched.
White House spokesperson Olivia Wales said of the June operations and the latest war that began in February, “Operation Midnight Hammer destroyed Iran’s nuclear facilities, and Operation Epic Fury built on that by destroying Iran’s defense industrial base, which it had used as a shield in its pursuit of nuclear weapons.”
“President Trump has long made clear that Iran can never have a nuclear weapon — and he’s not bluffing.”
The Office of the Director of National Intelligence did not respond to a request for comment.
Stopping Tehran’s nuclear program is a key U.S. goal
U.S. officials, including Trump, have repeatedly made eliminating Iran’s nuclear program a key goal of the war.
“Iran must not be allowed to acquire a nuclear weapon. That is the goal of this operation,” Vice President J.D. Vance wrote on X on March 2.
Sources said the unchanged estimate of how long it would take Iran to build such a weapon partly reflects the focus of recent U.S. and Israeli military operations.
While Israel struck nuclear-related targets including uranium processing facilities in late March, U.S. attacks have focused on conventional military capabilities, Iran’s leadership and its military-industrial base.
Some analysts said the unchanged forecast could also be due to the lack of major nuclear targets that can be easily and safely destroyed following the military operation in June.
Eric Brewer, a former senior U.S. intelligence analyst who oversaw the review of Iran’s nuclear program, said it was not surprising that the assessment had not changed because recent U.S. strikes have not prioritized nuclear-related targets.
“As far as we know, Iran still has all of its nuclear material,” said Brewer, vice president of the Nuclear Materials Research Program at the Nuclear Threat Initiative arms control think tank. “This material may be located in a deeply buried underground location that would be impenetrable to U.S. munitions.”
In recent weeks, U.S. officials have considered dangerous actions that would severely hamper Iran’s nuclear efforts. The options include conducting ground raids to retrieve highly enriched uranium believed to be stored in the Isfahan tunnel complex.
Iran has repeatedly denied seeking nuclear weapons. U.S. intelligence agencies and the International Atomic Energy Agency say Tehran halted work on the warhead in 2003, although some experts and Israel claim it kept key parts of the program secret.
Possible effects of killing scientists
Accurately assessing Iran’s nuclear capabilities is difficult even for the world’s leading intelligence services, experts say.
Several U.S. intelligence agencies have independently studied Iran’s nuclear program, and while sources say there is broad consensus about Iran’s ability to build a nuclear weapon, biased assessments do exist.
It is possible that Iran’s nuclear ambitions may be further frustrated than intelligence estimates indicate.
Some officials, including U.S. Secretary of State Marco Rubio, believe that U.S. strikes on Iran’s air defense systems would reduce Iran’s ability to defend its nuclear facilities, thereby reducing the nuclear threat if Iran decides to rush to weaponize in the future.
There is also the fallout from Israel’s assassination of Iran’s leading nuclear scientist.
David Albright, a former U.N. nuclear inspector who heads the Institute for Science and International Security, said the killings add significant uncertainty to Tehran’s ability to build a bomb that works as intended.
“I think everyone agrees that knowledge can’t be bombarded, but know-how can certainly be destroyed,” he said.
(Reporting by Gram Slattery, Jonathan Landay and Erin Banco; Editing by Don Durfee and Daniel Wallis)
