US, Israel Cripple Iran’s Nuclear Weaponization Work, New Report Shows

More than two months into the war, Iran’s ability to develop nuclear weapons has suffered a major setback as US and Israeli strikes have ravaged critical facilities, crippled essential infrastructure, and killed personnel central to Tehran’s nuclear ambitions, according to a new analysis

On Friday, the Institute for Science and International Security (ISIS), a Washington, DC–based think tank, released a new assessment of the impact of Israeli and US strikes on Iran’s nuclear program, concluding that the attacks significantly damaged Tehran’s ability to advance nuclear weapons development, particularly by disrupting its weaponization activities.

A nuclear program generally begins with uranium enrichment, the process of producing material that can power civilian reactors or, at higher levels of purity, be used in a nuclear weapon. Much of Iran’s enrichment infrastructure was destroyed during last year’s 12-day war.

The second element is weaponization, which involves the design, testing, and production of the components needed to assemble a functioning nuclear device — a central focus of the more recent Israeli and US military campaign.

According to ISIS’s newly released report, at least six confirmed nuclear-related sites were destroyed so far, with three additional locations possibly connected to the program also struck, bringing the total number of targeted facilities linked to nuclear weapons development to between nine and 12.

Since the start of the war earlier this year, Israel and the United States have struck a wide range of military-industrial facilities involved in missile, drone, and conventional weapons production.

However, the report indicates that some previously undisclosed sites may also have had connections to Iran’s nuclear activities, potentially raising the true scale of the damage.

By analyzing satellite imagery, the report concludes that Iran’s ability to successfully complete a nuclear weapon has been significantly degraded, with the strikes greatly extending the timeline required to produce a bomb while sharply increasing the likelihood of technical failure.

Before the June 2025 war, intelligence assessments estimated Iran could likely produce a nuclear weapon in less than six months with a high probability of success.

Now, the regime’s chances of successfully completing the weaponization process are considered technically low even over a one- to two-year period, largely because the strikes destroyed not only facilities, but also critical equipment and personnel involved in the final stages of bomb development.

ISIS’s latest findings contradict earlier US intelligence assessments, which reportedly concluded that Iran’s nuclear timeline had not been significantly delayed, arguing that such data is inconsistent with extensive visible destruction across key nuclear sites.

The report also argues that there are no signs Iran has resumed uranium enrichment activities, as facilities repeatedly targeted by Israeli and American airstrikes remain heavily damaged with no detectable reconstruction efforts underway.

Despite extensive damage to the regime’s infrastructure, the report cautions that Iran’s nuclear threat has not been fully eliminated.

ISIS has identified tunnel complexes near Esfahan and Natanz in central Iran that were not directly targeted and are believed to contain most of Iran’s enriched uranium stockpile, including roughly 440 kilograms enriched to 60 percent — far above civilian requirements and much closer to weapons-grade material.