U.S. strikes leave Iran’s nuclear timeline largely intact, intelligence finds

Two sources said U.S. intelligence agencies had concluded before June’s 12-day war that Iran could likely produce enough weapons-grade uranium and assemble a bomb in about three to six months.

After June strikes on nuclear sites in Natanz, Fordow and Isfahan, that timeline moved to about nine to 12 months, the sources said. Some facilities were badly damaged or destroyed, but the location of about 440 kilograms of uranium enriched to 60% remains unknown. The International Atomic Energy Agency estimates that amount would be enough to produce up to 10 nuclear warheads if enriched further.

U.S. officials say their main goal remains preventing Iran from obtaining a nuclear weapon, including through negotiations. But intelligence estimates have changed only modestly, partly because the latest strikes did not focus directly on nuclear infrastructure and because deeply buried underground sites are difficult to destroy.

The sources said the estimate of how long Iran would need to build a nuclear weapon remains largely unchanged partly because of the focus of the latest U.S. and Israeli military campaign. Israel struck nuclear facilities, including a uranium processing plant in late March, while the United States focused more on Iran’s conventional military capabilities, leadership and military-industrial base.

Some analysts believe the estimates may also reflect the fact that after the June military action, few major nuclear targets remained that could be destroyed easily and safely.

“Iran, as far as we know, still has all of its nuclear material. It’s probably in deeply buried underground facilities where U.S. munitions can’t penetrate,” said Eric Brewer, vice president of the Nuclear Materials Security Program at the Nuclear Threat Initiative, an arms control think tank.

Reuters reported that in recent weeks, U.S. officials considered risky operational options that could seriously complicate Iran’s nuclear program, including ground raids to seize highly enriched uranium believed to be stored in an underground tunnel complex near Isfahan.

Iran denies that it intends to build nuclear weapons. U.S. intelligence and the IAEA say Tehran shut down its warhead development program in 2003, though some experts believe parts of it may have survived.

Experts say even top intelligence agencies struggle to assess the true state of Iran’s nuclear program.

Several U.S. intelligence agencies have separately examined Iran’s nuclear program. While there is broad agreement on Iran’s ability to build a nuclear weapon, alternative assessments occasionally emerge. Reuters added that Iran’s nuclear ambitions may have been pushed back further than current intelligence estimates suggest.

David Albright, a former UN nuclear inspector and head of the Institute for Science and International Security, said the killings of leading Iranian nuclear scientists likely deepened uncertainty about Iran’s ability to build a nuclear weapon that would work properly.

“I think everyone agrees: You can’t bomb away knowledge, but you can certainly destroy know-how,” he said.

The Wall Street Journal reported that Tehran is no longer demanding the lifting of the blockade of the Strait of Hormuz as a condition for opening talks with the United States. Instead, Iran has proposed discussing the strait’s reopening, security guarantees and its nuclear program at the same time.

The newspaper said Iran signaled through intermediaries that it is ready to hold a new round of talks in Pakistan this week if Washington accepts the new proposal as the basis for dialogue.