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.