Trump says Iran could face harsher strikes if proxies 'cause trouble' as talks with Tehran begin

US President Donald Trump on Sunday warned Iran that it could face fresh military action if Tehran failed to restrain its regional proxies, as American and Iranian officials opened a new round of peace talks in Switzerland.

In a post on Truth Social, Trump referred to last week's US strikes on Iran and threatened stronger action if Iran-backed groups, particularly Hezbollah in Lebanon, continued activities viewed as destabilising by Washington.

“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 wrote.

The warning came as delegations from the United States and Iran gathered at the Burgenstock resort in Switzerland for talks aimed at building on an initial agreement reached last week to end hostilities between the two countries.

US Vice President JD Vance described the meeting as a significant opportunity to reshape relations between Washington and Tehran.

“This is a historic meeting,” Vance said, adding that the talks could potentially transform relations in the Middle East.

“The question before us now is how much more can we accomplish together? 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,” he said.

The US delegation includes Vance, Trump's son-in-law Jared Kushner and Special Envoy Steve Witkoff.

Iran is being represented by Foreign Minister Abbas Araghchi and chief negotiator Mohammad Bagher Ghalibaf.

Pakistan and Qatar are acting as mediators in the negotiations.

The talks follow an agreement signed last week aimed at ending the conflict between the United States and Iran and establishing a framework for broader discussions on regional security, economic issues and Iran's nuclear programme.

While both sides have expressed support for continuing dialogue, Trump's latest warning underscored the fragile nature of the process and the challenges that remain in securing a long-term settlement.