The Israeli attack on Iran in late October targeted and destroyed a top-secret Iranian nuclear weapons research facility in Parchin, severely hindering Iran's progress in nuclear weapons development, Axios reported, citing three U.S. and two Israeli officials.  

The facility, known as Taleghan 2, was located within the Parchin military complex, approximately 20 miles southeast of Tehran. The strike on October 25 decimated the site, which Israeli and U.S. intelligence claim was part of Iran's covert efforts to resume nuclear weapons research under the guise of civilian scientific activity.  

The attack reportedly eliminated sophisticated equipment critical to designing the plastic explosives used to detonate nuclear devices, according to a former Israeli official briefed on the operation. High-resolution satellite imagery from the Institute for Science and International Security confirmed the facility was completely destroyed.  

Taleghan 2 had previously been part of Iran's Amad nuclear weapons program before the military aspect was halted in 2003. Recent activity at the site included computer modeling, metallurgy, and explosive research that could potentially be applied to nuclear weapons development, U.S. officials said.  

“They conducted scientific activity that could lay the ground for the production of a nuclear weapon. It was a top-secret thing. A small part of the Iranian government knew about this, but most of the Iranian government didn't," one U.S. official stated.  

The U.S. had detected suspicious activity at Parchin earlier this year and directly warned Iranian officials in June. The warnings, however, were ignored, with Iran reportedly continuing its research.

"There was concern across the board" about Iranian activity at Taleghan 2 in the months leading up to the Israeli strike, a U.S. official noted.  

The decision to target Taleghan 2 was reportedly tied to Iran’s massive missile attack on October 1, with Israel seeking to deliver a retaliatory blow. Despite U.S. President Joe Biden’s request for Israel to avoid attacking Iranian nuclear facilities to prevent escalation into full-scale war, the strike proceeded.  

Notably, the Taleghan 2 site was not part of Iran's declared nuclear program. This meant Tehran could not publicly acknowledge the strike's significance without admitting to violations of the nuclear non-proliferation treaty.  

Israeli and U.S. officials described the operation as a demonstration of Israel’s deep intelligence capabilities within Iran.

"The strike was a not-so-subtle message that the Israelis have significant insight into the Iranian system, even when it comes to things that were kept top secret and known to a very small group of people in the Iranian government," a U.S. official said.