U.S. Vice President J.D. Vance was arriving Sunday (June 21, 2026) in Switzerland to help formally launch negotiations with Iranian leaders over curbing Tehran’s nuclear programme and building out the fragile interim deal to end the war in Iran.

The framework was signed last week, and now top U.S. and Iran negotiators are in a 60-day sprint to reach agreement on the technical details that hold massive implications for the world economy and global security.

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Yet the first days of that two-month period were complicated by the heavy exchange of fire in Lebanon between Israel and the Iranian-backed militant group Hezbollah — and by the subsequent announcement by Iran’s military that it had closed the Strait of Hormuz, the vital waterway that transits a fifth of the world’s traded oil and natural gas.

Mr. Vance had originally been slated to be on the ground at the picturesque Bürgenstock resort near Lucerne on Friday (June 19, 2026), but his departure from the United States was delayed after fighting escalated in Lebanon and Iranian officials canceled plans to attend the talks.

U.S. Central Command disputed Iran’s claim that it had once again shuttered the strait and said U.S. forces continued to monitor the situation to ensure traffic continues to flow through the waterway. Vance has said that millions of barrels of oil have moved through the strait in recent days.

Mr. Vance departed the U.S. just after Iranian state TV said Iran’s negotiators had arrived in Switzerland. Tehran’s negotiators include parliamentary speaker Mohammad Bagher Qalibaf and Foreign Minister Abbas Araghchi, along with central bank and oil officials.

The U.S. Vice President joins special envoy Steve Witkoff and Jared Kushner, President Donald Trump's son-in-law, who have already been on the ground to begin sifting through the technical details of the nuclear talks.

The talks between U.S. and Iran will also include Pakistani Prime Minister Shehbaz Sharif and army chief Field Marshal Asim Munir, as well as Qatari mediators.

While Mr. Vance said he planned to be in Switzerland for just “a day or two,” leaving much of the detailed negotiations to be spearheaded by Witkoff and Kushner, his role in the talks has heightened the scrutiny of the vice president at a time when he’s actively considering a 2028 presidential campaign.

Mr. Trump and Mr. Vance have come under searing criticism from parts of their own party for the deal, with Republican hard-liners unfavorably likening it to a nuclear agreement signed by the Obama administration that Trump and the GOP have insisted did nothing to actually terminate Iran’s nuclear program.

The agreement signed by Mr. Trump and Iranian President Masoud Pezeshkian immediately allows Tehran to sell its oil freely and paves the way for Iran to tap into billions of dollars in assets that are currently frozen. It also calls for Iran to dilute its stockpile of highly enriched uranium, believed to be buried under nuclear sites that were targeted in U.S. strikes last summer.

The agreement says commercial vessels can pass through the Strait of Hormuz for 60 days without a charge, but does not preclude future fees imposed by Iran. Trump made his own threat on Saturday (June 20, 2026) to levy U.S. tolls on the strait if there is no deal with Iran in 60 days, insisting in a social media post that the money would be for “services rendered as the Guardian Angel to the countries of the West Asia.”

Further complicating matters, neither Israel nor Hezbollah are signatories to the deal between the U.S. and Iran, and Israeli Prime Minister Benjamin Netanyahu has vowed to keep his forces in southern Lebanon until any threat to Israel is eliminated. Hezbollah has refused to halt its attacks unless Israel commits to withdrawing from Lebanon.

Fighting between Israel and Hezbollah in the initial days after the agreement between the U.S. and Iran killed 47 people in Lebanon, as well as four Israeli soldiers.