Speaking to reporters before departing the Iran-U.S. negotiations in Bürgenstock, Switzerland, Vance said that technical talks aimed at reaching a final agreement would take several weeks and that "we have laid a very strong foundation for a successful final agreement."
He stated that Iran has agreed to invite IAEA inspectors into the country, adding that the inspectors' return could take place this week, or even as early as today.
Vance described the move as "a major achievement for the American people and the first step toward the permanent nuclear disarmament of Iran, or the permanent end of Iran's nuclear weapons program."
The International Atomic Energy Agency estimates that Iran possesses approximately 440 kilograms of uranium enriched to 60 percent, a level close to that required for producing weapons-grade material.
Since the U.S. strikes on the Fordow, Natanz, and Isfahan nuclear facilities on June 22, 2025, during the 12-day war, Iran has denied IAEA inspectors access to those sites and has reduced its cooperation with the United Nations nuclear watchdog.
Iranian officials had previously rejected the return of IAEA inspectors.
On Friday, Iranian Foreign Ministry spokesperson Esmaeil Baghaei said: "Inspections of facilities to which the IAEA's access was suspended due to military attacks will depend on the course of negotiations and their outcome."
Vance said he expects discussions regarding the inspectors' return to begin very soon.
"At the very least, I expect that to happen this week," he said. "In fact, we believe that some of those discussions with the inspectors and with the Agency may even begin today."
On Sunday, IAEA Director General Rafael Grossi wrote on X that he was in Bürgenstock, where he met with Swiss Foreign Minister Ignazio Cassis.
In another part of his remarks, the U.S. vice president said the negotiations in Switzerland had made "very good progress." Referring to discussions on the release of Iran's frozen assets, he said, "We want to establish a process that ensures these assets reach the Iranian people, rather than being spent on terrorism."
