By Michael R. Gordon and Laurence Norman

Iran's atomic program hasn't advanced significantly since the U.S. and Israel struck its three main nuclear sites last June, according to experts and diplomats, despite Washington's top negotiator saying Tehran could make fissile material for a bomb within days.

The appraisal, which is widely accepted by officials and researchers who study Iran's nuclear activities, comes as U.S. and Iranian officials prepare to hold talks on Thursday that could determine whether President Trump orders military action against the country.

The lack of visible evidence of significant progress in Iran's nuclear ambitions since last year raises questions about the Trump administration's publicly stated rationale for launching a potentially major war in the Middle East. President Trump has said he would prefer a deal but is prepared to use force to ensure Iran never acquires a nuclear weapon.

"Viewing the satellite imagery and monitoring the Iranian nuclear sites, we don't see any evidence that they are trying to reconstitute their nuclear-weapons program." said David Albright, a former United Nations weapons inspector and president of the Institute for Science and International Security, which analyzes nuclear issues. "They are essentially on hold."

Steve Witkoff, the U.S.'s chief negotiator with Iran, told Fox News last week that Iran is "probably a week away from having industrial-grade bomb-making material."

That assessment would imply that a significant part of Iran's uranium-enrichment capability survived last year's strikes -- and that Iran can also still access some of its enriched-uranium stockpiles, which were believed to have been buried under rubble last June. Many analysts are skeptical that Iran could easily do so at the bombed facilities.

In his State of the Union address on Tuesday, Trump said Iran was still pursuing its nuclear ambitions but didn't detail any new activities.

"After Midnight Hammer, they were warned to make no future attempts to rebuild their weapons program, in particular, nuclear weapons," the president said. "Yet they continue, starting it all over. We wiped it out, and they want to start all over again and are at this moment again, pursuing their sinister ambitions."

The White House said last year's strikes "obliterated" Iran's nuclear facilities but that Trump wants to ensure it can't revive its program and threaten America.

Trump has demanded that Iran also curb its ballistic-missile program, stop support for proxy militias in the Middle East and cease its brutal repression of street protests.

But Iran's nuclear program, in particular its enrichment of uranium, is at the crux of the negotiations.

The absence of regular U.N. inspections means that the exact scope of Iran's current nuclear activities can't be known for certain, experts caution.

Some analysts say Iran has undertaken some work that could allow it to resume enrichment eventually -- and has taken measures to protect what is left of its nuclear sites against renewed U.S. strikes.

Iran denies it has ever sought to build a nuclear weapon, but the U.N. atomic agency has documented years of Iranian nuclear-weapons-related work. Iran is the only non-nuclear-armed country that is known to have enriched uranium to 60%, or near-weapons grade.

Tehran insists it has a right to enrich uranium, a critical element of a nuclear-weapons program that can also be used for civilian purposes.

However, the head of the International Atomic Energy Agency, Rafael Grossi, said in October that there was no evidence Iran has resumed the enrichment of uranium since the U.S. strikes in June. Grossi's assessment hasn't changed, according to a person familiar with his thinking, and it is widely accepted by nuclear experts.

The U.N. agency has the "firm impression" that Iran's stockpiles of highly enriched uranium still lie buried at the sites bombed last June, Grossi said earlier this month.

"There's a general conclusion today that there's a de facto suspension of enrichment," said Robert Einhorn, a former senior State Department official for nonproliferation issues and a senior fellow at the Brookings Institution. "There's no enrichment taking place."

U.S. forces dealt a major setback to Iran's nuclear program in the Pentagon's Midnight Hammer operation in June when B-2 bombers dropped 14 massive bombs on the country's Fordow and Natanz sites while submarine-launched cruise missiles struck facilities at Isfahan.

"Iran's key nuclear-enrichment facilities have been completely and totally obliterated," Trump said on the day of the strikes.

Pentagon spokesman Sean Parnell said in July that Iran's program had been set back by "one to two years."

Iran has reasons to be cautious about reviving its nuclear activities, said Nate Swanson, who served as Iran director at the National Security Council and as a senior State Department adviser on Iran until last summer. The risk of being caught by U.S. or Israeli intelligence is high.

"Iran probably has low confidence that they can initiate a breakout without being spotted," Swanson said. "I think we would know."

Israel has demonstrated for years that its intelligence services have deeply penetrated Iran's nuclear work and planning, culminating in Israeli strikes last summer that killed more than a dozen of Tehran's top nuclear scientists.

Satellite images show that some activity has taken place at the Isfahan site. There is no evidence that Iran is making much effort to the Fordow and Natanz sites. Nor has evidence emerged that Tehran has tried to recover enriched uranium buried underground.

In recent weeks, Tehran has been working to better protect its main nuclear sites from another round of U.S. bombing, pouring soil and concrete over the sites' entrances to harden their defenses.

Satellite images indicate continuing work on a tunnel network beneath Pickaxe Mountain, near the Natanz enrichment site. The tunnels were undamaged last summer even as Natanz was heavily bombed. There have also been signs of reconstructed weapons-related work at the Parchin military site, which Israel bombed last summer and in 2024.

"It's possible that Iran has machine tools and materials, spare parts hidden away somewhere. And that might allow them to reconstruct a small centrifuge facility," said Gary Samore, director of the Crown Center for Middle East Studies at Brandeis University and a former White House official on weapons of mass destruction during the Obama administration. "But as far as we know, they haven't done that."

In his State of the Union speech, Trump also said that Iran's missile program presented a looming danger.

"They've already developed missiles that can threaten Europe and our bases overseas, and they're working to build missiles that will soon reach the United States of America," Trump said.

A report by the U.S.'s Defense Intelligence Agency last May said Iran was working on space launch vehicles that could potentially adapt to develop an intercontinental ballistic missile by 2035, "should Tehran decide to pursue the capability."

Iran has tested a space-launch vehicle on two occasions since last June, experts say. The second test is believed to have malfunctioned, said Behnam Ben Taleblu, a senior director of the Iran program for the Foundation for Defense of Democracies.

"Given that those technologies are nearly identical to what Iran would need for an IBCM, this should be cause for concern," Taleblu said.

But a space launch system doesn't include a re-entry vehicle with heat shielding that could protect a potential nuclear payload over an intercontinental distance. It isn't known how close Iran is to developing those capabilities, Taleblu said.

Write to Michael R. Gordon at michael.gordon@wsj.com and Laurence Norman at laurence.norman@wsj.com

(END) Dow Jones Newswires

February 25, 2026 16:56 ET (21:56 GMT)

Copyright (c) 2026 Dow Jones & Company, Inc.