Iran and the United States agreed Monday to set up communications lines to keep the vital Strait of Hormuz open and end fighting in Lebanon, mediators said, after their first round of talks in Switzerland toward ending the war in the Middle East.

The teams led by US Vice President JD Vance and Iran’s Mohammad Bagher Ghalibaf opened talks Sunday, as part of a two-month negotiating period set out under a preliminary deal agreed last week.

Mediators Pakistan and Qatar said the negotiators reached agreement on a “roadmap towards reaching a final deal within 60 days”, with technical talks to continue for the rest of the week at the Swiss resort of Burgenstock.

“Encouraging progress has been made including the creation of a mechanism for further technical talks,” they said, detailing a contact channel set up to “avoid incidents and miscommunication” at the Strait of Hormuz.

A “de-confliction cell”, between the parties and the Lebanese authorities has also been agreed to prevent fighting from erupting again, they said.

Iran’s Foreign Minister Abbas Araghchi wrote on X after the high-level talks in Switzerland, “Tireless Pakistani and Qatari mediation has delivered major progress to end Lebanon War.”

“Oil and petrochem exports are waived, blockade lifted, some frozen assets released, and major reconstruction & development plan launched for Iran. 1st real test: Lebanon deconfliction cell,” he wrote.

There was no immediate reaction from US negotiators, but crude prices slipped while stocks mostly gained in Asia as the progress reported by mediators fueled optimism.

The development came after a shaky start to the negotiations, with the Islamic Republic’s delegation walking out in response to US President Donald Trump’s threats to strike Iran over its support for Hezbollah Sunday.

Trump had warned of new attacks on Iran if it did not “immediately stop their highly paid PROXIES in Lebanon from causing trouble”.

Iran hit back with a warning of its own.

“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,” Iran’s chief negotiator Mohammad Bagher Ghalibaf said.

Israeli Prime Minister Benjamin Netanyahu meanwhile said troops would remain in south Lebanon “as long as necessary” and vowed that he would “not allow Iran to acquire nuclear weapons”.

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.

The fighting between Israel and Hezbollah has repeatedly threatened to derail peace efforts.

On Friday, planned US-Iranian talks were postponed after Israel launched deadly strikes in Lebanon following the deaths of four of its soldiers in combat there. (AFP)