US and Iran publicly trade threats as talks take place in Switzerland

As negotiations aimed at finalising a peace deal went on behind closed doors between the US and Iran in Switzerland, each side issued public threats towards the other as key sticking points risk derailing efforts to end the war.

The peace talks look to end a war that has sowed severe instability across the Middle East rattled the global economy, and are meant to trigger a 60-day period to settle issues that have plagued US-Iran relations for decades.

However, just as the talks kicked off, US President Donald Trump threatened to renew strikes on Iran if it did not stop Hezbollah from "causing trouble" in Lebanon.

In a post on his Truth Social platform, Trump said "If they don’t, we’ll hit Iran very hard again, just like we did last week, only harder."

The negotiations opened against a backdrop of clashes in recent days between the Israeli army and the Iran-backed Hezbollah militant group in southern Lebanon.

The memorandum of understanding signed on Wednesday between the United States and Iran stipulates a cessation of hostilities on all fronts, including in Lebanon.

Iran's chief negotiator Mohammad Bagher Ghalibaf later responded to Trump's threat, warning the United States that "our armed forces are ready to respond".

"Don't they think that if their threats had any effect, they would not have reached today's state of desperation? We do not take American threats into account," Ghalibaf added.

"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."

Lebanon remains a sticking point

Israeli Prime Minister Benjamin Netanyahu also weighed in, repeating his government's position that Israeli forces would remain in southern Lebanon "as long as necessary", while also vowing to prevent Iran from acquiring nuclear weapons.

"We will remain in the security zone in southern Lebanon for as long as necessary to protect the cherished residents of the north and all the citizens of Israel... Nothing will alter that commitment," Netanyahu said.

"And with regard to Iran: whatever political developments may unfold, I will not allow Iran to acquire nuclear weapons. As long as I serve as prime minister of Israel, that will not happen."

Hezbollah chief Naim Qassem rejected any Israeli security zone in Lebanon, saying Israeli troops "remaining on Lebanese land is impossible."

The talks to end the months-long conflict are also taking place with Iran yet again closing the strategic Strait of Hormuz in response to the recent Israeli attacks on Lebanon.

"It is not possible to enter the negotiation phase for a final agreement" unless there is an end to the war in Lebanon, foreign ministry spokesman Esmaeil Baqaei wrote on X.

By Sunday evening, there had been no reports of Israeli strikes or continued fighting, with some residents of southern Lebanon cautiously trickling back to their homes.

Vance hopes to turn 'new leaf' with talks

US Vice President, who was in Switzerland alongside US negotiators Jared Kushner and Steve Witkoff, earlier in the day hailed "a historic meeting" and expressed hopes of turning a "new leaf" with Iran.

"The question before us now is how much more can we accomplish together?", Vance said, adding: "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 it's certainly very much something that can happen."

The US is looking to get Iran locked into negotiations over its nuclear programme amid concerns it may be used for military purposes, which Iran denies.

Vance also wants to push Tehran to commit to keeping open the Strait of Hormuz, the critical waterway through which about a fifth of world traded oil passes.

Iranian state media reported on Sunday that the Islamic republic's nuclear programme were not discussed, though this was not independently verified.

Iranian President Masoud Pezeshkian said Tehran would not relinquish its right to enrich uranium, though he repeated Iran's denial that it wants nuclear weapons.

"We can also state in writing that we have no intention of building a bomb," he said on the presidential website.