U.S. envoy Steve Witkoff and White House adviser Jared Kushner traveled to Oak Ridge National Laboratory in Tennessee on Thursday to consult experts who could play a role in negotiations with Iran over its nuclear ambitions.

The U.S. and Iran remain at odds on several details of a memorandum of understanding that would end the conflict and begin talks on Tehran's nuclear program, Axios reported Friday, citing U.S. officials and regional sources involved in the mediation.

A source familiar with the trip confirmed Axios' report to Reuters but did not provide further details.

"This meeting in Oak Ridge doesn't mean that a deal is going to happen, but it is a sign that the negotiations are in a very serious phase and that there is a good chance to get it done and we want to be prepared," a U.S. official told Axios.

Iran is believed to retain much of its stockpile of highly enriched uranium, including material that was at sites targeted by U.S. B-2 Spirit bombers in June 2025. Tehran has been adamant that it must maintain the ability to enrich uranium and denies developing a weapon.

The International Atomic Energy Agency said Iran has about 440.9 kilograms, or 972 pounds, of uranium enriched to 60%. That is far above the 3% to 5% enrichment typically needed for civilian nuclear power, or even the roughly 20% used for some research purposes. But it is not far below the roughly 90% enrichment generally considered weapons-grade.

Some of the country's foremost experts in uranium processing and centrifuge technology are based at Oak Ridge National Laboratory and the Y-12 National Security Complex, which is about 9 miles north of Oak Ridge. Nuclear materials and equipment, including material from Kazakhstan and Libya, have been routed through Tennessee.

The White House declined to comment to Axios. The National Nuclear Security Administration also declined to comment.

The two U.S. officials told Axios a team of roughly 100 experts was recently established to take part in the nuclear negotiations should a preliminary deal be reached. Witkoff and Kushner traveled to Tennessee to meet with members of that team and discuss preparations for the potential implementation of a nuclear deal.

Witkoff and Kushner, President Donald Trump's son-in-law, agreed to terms with their Iranian counterparts last week on a 60-day MOU to extend a two-month ceasefire, reopen the Strait of Hormuz, allow Iran to sell oil, and launch talks on Iran's enriched uranium stockpile and limitations on future enrichment.

Trump on May 29 requested two changes to the draft agreement, and the Iranians said they would ask for tweaks of their own. The U.S. is waiting for the official Iranian response, but the sources told Axios the gaps are relatively narrow.

If the negotiations advance to the second phase, the team of experts that met with Witkoff and Kushner in Tennessee would have to develop a plan for disposing of Iran's nuclear material. The team would also determine how to further limit the enrichment program and verify compliance.

U.S. officials said that some of the experts Witkoff and Kushner met Thursday helped recover enriched uranium from Venezuela several weeks ago. That material, from a research reactor, arrived last month in South Carolina for processing.

Some of the nuclear experts who attended the meeting also joined Kushner and Witkoff in Oman for nuclear talks with Iran before the war began.

"These are the top nuclear experts in the U.S. who know how to do the technical things that a deal with Iran will entail," a U.S. official told Axios.