US President Donald Trump on Sunday threatened to restart the war with Iran even as Vice President JD Vance met Iranian officials for the first talks under an interim peace ​deal, overshadowed by Tehran’s announcement it had again closed the Strait of Hormuz.

The talks in the Qatari-owned mountaintop resort of Buergenstock in Switzerland were the first to be held under the terms ‌of a MoU agreed a week ago.

It calls for the strait to be reopened and a halt to all hostilities, including in Lebanon, which US ally Israel invaded in March. But Iran, arguing that Washington had failed to meet its commitment to halt fighting in Lebanon, said it had shut the strait again and that Sunday’s talks would not cover substantive issues such as Iran’s nuclear programme.

“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!!!” Trump said, apparently referring to Iran’s Hezbollah allies in Lebanon, and to an escalation he ordered earlier this month.

Fox News reported that Trump had gone further in an interview, saying he ​had told Iranian officials if they closed the strait, “you won’t have a country”, and threatening to take over the waterway.

At the talks in Switzerland, where US and Iranian ⁠officials met in the presence of Qatari mediators, Vance played down the impact of violence in Lebanon, saying progress had been made towards ending hostilities there.

“These things are always a little bit messy,” he said.

Even as Trump was threatening ​Iran, Vance told reporters the US president had “asked us to turn over a new leaf to transform our relationship with the people of Iran”.

The warring sides did not pursue a joint photo opportunity at the talks. Before Vance made his remarks, ​Iran’s Foreign Minister Abbas Araghchi briefly walked into the room and embraced Pakistani Prime Minister Shehbaz Sharif, a mediator. Araqchi did not interact with Vance, who was at the back of the room.

Earlier on Sunday, Vance briefly appeared in front of travelling media ​as he, envoy Steve Witkoff and President Donald Trump’s son-in-law Jared Kushner met Pakistani Prime Minister Shehbaz Sharif and Pakistan’s Army Chief Field Marshal Asim Munir.

Warm greetings were exchanged, and Vance said, “What’s up, man?” as he shook hands with Munir and ‌hugged him. “My brother,” ⁠Munir said as he reached out to Witkoff and embraced him.

Iran cites Lebanon as reason to close Strait

Despite the announcement of a new ceasefire in Lebanon on Friday, there has been scant sign of an end to fighting there. Iran said on Saturday that as a result, it had again shut the strait, whose closure for nearly four months caused the biggest disruption of global energy supplies in ​history.

US officials disputed that the strait was closed, but commercially available shipping data showed an immediate impact.

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.

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. Throughout the war, shipping firms have said it is too dangerous to ‌traverse without Iran’s ⁠permission.

Iran said there could be no start to the next phase of talks, including over its nuclear programme, until the fighting ends and it gets promised economic benefits.