“At the same time as the talks began in Switzerland, Donald Trump published a message on X in which he repeated his threats and remarks against Iran.”
Iran later returned to the negotiating table and US delegates believed talks would continue through the night in Switzerland, a US diplomat told reporters.
The diplomat said the Iranian delegation was involved in “robust discussions on all elements of the nuclear deal”.
Earlier, Vance said the US hoped to “turn over a new leaf” with the Islamic Republic, and said that they had made “great progress”.
But his efforts appeared to be quickly unravelling after Trump’s intervention.
The talks in the scenic Qatari-owned Swiss mountain resort of Burgenstock were the first to be held after a memorandum of understanding was signed between Washington and Tehran last week.
Under the terms of that deal, the Strait of Hormuz would be reopened and there would be a ceasefire “on all fronts”, including Lebanon.
However, Hezbollah and Israel continued attacking each other and Tehran’s Islamic Revolutionary Guard Corps (IRGC) declared the strait closed.
On Sunday, Trump revealed to Fox News that he told Iranian officials: “You close the strait and you won’t have a country.
“You won’t even make it back to your f***ing country ... we’ll take over the rest of the country.
He added: “We may take over the Strait, if we have to. I’ll blow the s*** out of them.”
He then posted on Truth Social: “Iran must immediately stop their highly paid proxies in Lebanon from causing trouble. If they don’t, we’ll hit Iran very hard again, just like we did last week, only harder.”
The Iranian delegation to the talks was led by chief negotiator Mohammad Ghalibaf and included government, security, bank and oil officials.
They refused to pose for photographs with their US counterparts and then left the talks after Trump’s comments.
Ghalibaf later said, “We do not take American threats into account. They would do better to be careful with their statements; our armed forces are ready to respond to them in a different manner. No matter what they say, we are the ones who act.”
In addition to Vance, the US negotiating team includes envoys Steve Witkoff and Jared Kushner, Trump’s son-in-law.
Pakistan’s Prime Minister Shehbaz Sharif and the army chief, Field Marshal Syed Asim Munir, were also in Switzerland to participate in this weekend’s sessions as mediators, alongside a Qatari delegation.
Vance said, “The question is, can we turn over a new leaf? Can we change relations in the Middle East permanently, or do we go back to doing things the old way, which is not our preference but is certainly something that can happen.”
It is understood that talks never even reached the stage of discussing Iran’s nuclear programme. Instead, Iran insisted on ensuring the memorandum of understanding was implemented properly.
The fighting between Israel and Hezbollah has repeatedly threatened to derail peace efforts. Israel says it is not party to the US-Iran deal and will keep its forces in the Lebanese territory it occupies.
In a statement, its military said Israel was committed to the ceasefire but would act against any threats.
Hezbollah chief Naim Qassem rejected this position, saying Israeli troops “remaining on Lebanese land is impossible. There are no security zones for Israel. Israel is an aggressor and must leave”.
Lebanon’s health ministry says Israeli attacks have killed 4057 people since March 2, including medics, women and children. It did not say how many were Hezbollah fighters.
Israeli authorities say at least 32 soldiers and four civilians have been killed in fighting with Hezbollah.
On Sunday night, there was paralysis in the Strait of Hormuz once again.
Only a single small tanker crossed the waterway with its location-signalling transponders on after Iran’s announcement, compared with dozens of ships in recent days when traffic had begun returning to pre-war levels.
US Central Command said 55 merchant ships transited the strait on Saturday, carrying more than 17 million barrels of oil bound for global markets.
Iran’s Fars news agency cited a military source as saying on Sunday that no new permits were being issued for ships to cross until further notice.
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