Iran was nowhere close to a nuclear bomb, experts say

"According to an IAEA estimate, as of June 2025, Iran possessed 441 kilograms of 60 percent enriched uranium, where the percentage refers to the share of the isotope uranium 235 (U 235) found in the material. That would be enough for 10 nuclear weapons if the material could be enriched further to full 90 percent weapons-grade concentrations, according to the IAEA."

"That further enrichment would take a matter of weeks in a fully functioning Iranian nuclear complex, perhaps explaining the time line within Trump's declaration. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. That step alone doesn't equal a bomb, however."

"There was no evidence that Iran was close to a nuclear weapon, says Jeffrey Lewis of the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies. His comment echoed those of other experts after the war's start, as well as statements from International Atomic Energy Agency (IAEA) chief Rafael Grossi at that time and in 2025 and last year's threat assessment report by U.S. intelligence agencies."

President Trump claimed Iran could develop a nuclear weapon within two to four weeks, but nuclear experts including Jeffrey Lewis of the Middlebury Institute dispute this assessment. The IAEA reported Iran possessed 441 kilograms of 60 percent enriched uranium as of June 2025, sufficient for ten weapons if further enriched to 90 percent weapons-grade concentration. This additional enrichment could take weeks in a functioning nuclear complex, potentially explaining Trump's timeline. However, converting enriched uranium to an actual weapon requires additional steps beyond enrichment. Trump stated U.S. bombing of three underground Iranian facilities completely destroyed Iran's main enrichment capabilities, contradicting claims about Iran's current nuclear weapons production capability.

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