Mideast Live Updates: New Round of U.S.-Iran Talks Set to Start in Switzerland

The site where most of that material is believed to be stored was believed to be heavily damaged in U.S.-Israeli attacks last year. But without independent access to the area, the fate of the stockpile remains unclear.

For more than 50 years, Tehran has insisted that its nuclear program is for peaceful purposes only. But the United States is demanding assurances that Iran cannot secretly develop a weapon.

Here are four key areas the talks are likely to focus on:

Uranium Enrichment

The process of enriching uranium transforms it from fuel that can be used for civilian purposes, like energy production, into a crucial component of a nuclear weapon.

To prevent that from happening, the United States is demanding that Iran suspend all uranium enrichment for at least 20 years. The Iranians have countered with offers of a 10-year halt.

In a phone call with The New York Times on June 14, Mr. Trump hinted that he might settle for a 15-year suspension, but that said he didn’t want to negotiate via the news media. In the same call, he also suggested that Iran be limited to enriching at low levels “forever.”

Looming over the new talks is the deal struck by President Barack Obama in 2015 that negotiated a 15-year halt. Mr. Trump tore up that deal in his first term.

Vice President JD Vance, who is leading the American negotiation, stated on Thursday that the U.S. was seeking a complete a moratorium on all uranium enrichment by Iran over the suspension period.

“The Obama deal allowed the Iranians to enrich uranium. This deal will not,” Mr. Vance told reporters.

Mr. Obama’s deal limited enrichment to 3.67 percent, enough for research and medicine. Nuclear weapons typically require about 90 percent enrichment.

Current Stockpile

After Mr. Trump withdrew from the nuclear deal in 2018, Iran steadily increased its stockpile of near-bomb-grade material until it had enough to build at least 10 bombs. As of June 2025, the U.N. nuclear watchdog, the International Atomic Energy Agency, believed that Iran had about 970 pounds of uranium enriched to 60 percent, in addition to roughly 11 tons of uranium enriched to other levels.

The United States struck three key Iranian nuclear sites last year, including a complex outside Isfahan, where the U.N. agency said most of the near-bomb-grade material was stored. But with international inspectors barred from the site, the status of the enriched uranium is uncertain.

U.S. officials are insisting that Iran disposes of its stockpiles completely. According to two American officials, the United States is offering to work with the U.N. watchdog to dilute, or “downblend,” it to safe levels.

Another option would be for Iran to transfer the stockpile to another country, as it did with 98 percent of the cache under the 2015 deal. Iran has not said publicly whether it would be willing to give up its entire stockpile.

Nuclear Sites

The United States has insisted that Iran dismantle its two enrichment plants at Natanz and Fordo, as well as its uranium storage tunnels at Isfahan. It’s possible that Iran also has additional nuclear sites that the world doesn’t know about.

Tehran has balked, insisting that that would amount to surrendering its “right to enrich.” It has argued that at least one site should remain, though that might prove difficult for U.S. negotiators to stomach.

Under the Obama deal, Iran was permitted to keep facilities, as long as they were repurposed for civilian use. Critics of that deal say it meant that Iran was able to quietly revive nuclear enrichment after the 2015 deal collapsed.

Access for Inspectors

International inspectors haven’t had any visibility into Iranian nuclear sites since the U.S.-Israeli attacks last year prompted Tehran to block the U.N. agency’s access.

The Trump administration wants international inspectors to be able to conduct “snap” visits at any time and at any site in Iran. Rafael M. Grossi, the head of the U.N. watchdog, said on Thursday that both Iran and the United States wanted his agency to have a role in verifying their agreement.

Prospects for an Agreement

Resolving all of these questions within the 60-day negotiating timeline set out by the initial U.S.-Iran deal will be a tall order, said Darya Dolzikova, an expert in nuclear weaponry at the Royal United Services Institute, a London-based research group. The 60-day window is extendable by mutual consent, and Mr. Trump said this past week that it was not a “hard” deadline.

For one thing, she said, the two sides would need to establish the current status of Iran’s nuclear program and stockpile, an extensive exercise.

“If you’re going to start negotiating away parts of Iran’s program and potentially even accepting certain elements of it,” Ms. Dolzikova said, “then we need to have a sense of what they have now.”

“I don’t want to say it’s not possible,” she said, “but these are very complex issues, and 60 days is not a lot of time.”