Negotiators from the United States and Iran are set to begin peace talks in Switzerland on Sunday, even as Washington disputes Tehran’s claim that it has closed the Strait of Hormuz, one of the world’s most important energy corridors.
High-level Iranian officials arrived in Switzerland ahead of the talks, Iranian state media reported, while U.S. Vice President JD Vance left Washington for meetings expected to begin on Sunday. Pakistan, which helped broker the interim agreement between the two sides, said Prime Minister Shehbaz Sharif and army chief Field Marshal Syed Asim Munir would also attend the sessions.
The talks follow a 60-day ceasefire agreed by Washington and Tehran as part of an interim deal signed on Wednesday by U.S. President Donald Trump and Iranian President Masoud Pezeshkian. The agreement is aimed at ending nearly four months of war and opening negotiations on Iran’s nuclear programme, regional security and sanctions.
But tensions rose sharply on Saturday after Iran’s Islamic Revolutionary Guard Corps declared the Strait of Hormuz closed, citing Israeli attacks in Lebanon and accusing Washington of failing to enforce a ceasefire “on all fronts.”
U.S. Central Command rejected the claim, saying 55 merchant ships passed through the strait on Saturday, carrying more than 17 million barrels of oil to global markets. The command said U.S. forces would continue to ensure freedom of navigation and the uninterrupted flow of commercial traffic.
The Strait of Hormuz is a vital passage for global oil and gas supplies, and any real disruption could trigger sharp market volatility and deepen fears over energy security.
Trump said no toll would be imposed on ships using the strait during or after the ceasefire, unless talks collapse. In a social media post, he raised the possibility of a U.S. charge for protecting regional shipping if a final agreement is not reached, describing Washington as the “Guardian Angel” of Middle Eastern countries.
Iranian officials, however, accused the United States of failing to uphold the first clause of the interim deal, which Tehran says requires a ceasefire across all fronts, including Lebanon.
Mohammad Mokhber, an adviser to Iran’s supreme leader Ayatollah Mojtaba Khamenei, said the flow of Middle Eastern energy would remain halted as long as the agreement existed only “on paper.”
Iran’s delegation is reportedly led by chief negotiator Mohammad Baqer Qalibaf and includes Foreign Minister Abbas Araqchi, along with senior security, central bank and oil officials. The U.S. team includes Vance, envoy Steve Witkoff and Jared Kushner.
Iranian Foreign Ministry spokesperson Esmaeil Baghaei said Tehran would use the Switzerland talks to demand implementation of commitments, pointing to what he described as repeated failures by the other side to honour past agreements.
Vance told Fox News he remained confident the ceasefire would hold and said he had seen no evidence that the Strait of Hormuz had been closed. Before departing from Joint Base Andrews, he said negotiators were likely to hold “a couple days of talks.”
“I think we’re going to hopefully make progress on the nuclear issue, make progress on the Lebanon ceasefire issue,” Vance said.
The Lebanon front remains one of the most fragile parts of the agreement. A halt to fighting there was among the conditions for opening the U.S.-Iran talks, but Lebanese Civil Defence said Israeli strikes killed 20 people on Saturday, only hours after the truce took effect.
Israel said it was responding to Hezbollah attacks, while Hezbollah said it would not allow Israel “freedom of movement” inside Lebanon. Israel has said it is not a party to the U.S.-Iran deal and will continue to defend its forces in Lebanese territory it occupies.
An Israeli military statement said the army remained committed to the ceasefire but would act against any threat to Israel or its forces. Channel 12 reported that Prime Minister Benjamin Netanyahu and the defence minister had instructed the military to hold fire, while making clear that Israeli forces would not withdraw from captured areas.
Lebanon’s state news agency said Israeli warplanes and drones struck locations across southern Lebanon and the Bekaa Valley, both Hezbollah strongholds. An Israeli military official said Hezbollah had fired more than 50 projectiles at Israeli forces in southern Lebanon overnight, prompting retaliatory strikes.
A Hebrew University poll shared with Reuters found that 92% of Israelis believe Iran benefited more than Israel from the joint Israeli-U.S. military campaign. Nearly 90% said the goals of the war had not been met, while more than 70% said they did not believe Netanyahu’s claims of major achievements.
Lebanon’s health ministry says 4,057 people have been killed in Israeli attacks since March 2, including medics, women and children. It does not specify how many of the dead were combatants. Israeli authorities say at least 32 soldiers and four civilians have been killed in fighting with Hezbollah.
The Switzerland talks now open under intense pressure, with Washington trying to preserve the ceasefire, Tehran demanding enforcement across the region, and Lebanon threatening to derail the wider diplomatic track before negotiations begin.