Technical-level talks between the United States and Iran are to begin immediately following a first round of negotiations between senior officials in Switzerland, mediators Qatar and Pakistan said in a joint statement.
The talks are aimed at reaching a "final deal" within 60 days, in line with the memorandum of understanding announced earlier, the statement released early on Monday said.
Working groups are to be established to address Iran's nuclear programme and Western sanctions, among other issues.
The talks took place in a "positive and constructive atmosphere," the mediators said, adding that "encouraging progress" had been achieved, including the creation of a "mechanism for further technical talks."
The mediators also said a communication channel had been set up between the parties to prevent misunderstandings or incidents in the Strait of Hormuz and ensure safe passage for ships through the strategic waterway.
The statement also said a "de-confliction cell" had been created to help ensure compliance with the ceasefire in Lebanon, where there have repeatedly been attacks between the Israeli army and the pro-Iranian Hezbollah militia.
Technical discussions on implementing the agreements are expected to continue throughout the week at the Bürgenstock resort near Lucerne, the statement said.
Iran says 'major progress' made on Lebanon
Iranian Foreign Minister Abbas Araghchi wrote on X that there had been "major progress" in efforts to end the war in Lebanon. He said the Lebanon de-confliction cell would be the first "real test" of the agreements.
"Oil and petrochem exports are waived, blockade lifted, some frozen assets released, and major reconstruction & development plan launched for Iran," Araghchi wrote.
His claims could not initially be independently verified. The US side did not immediately comment on the outcome of the first day of talks.
Qatari Prime Minister Mohammed bin Abdulrahman Al Thani posted a photo early on Monday on X showing him with US Vice President JD Vance and Jared Kushner, the son-in-law of President Donald Trump.
"Live from Lucerne, work continues," he wrote. In the photo, Vance appears to be typing on a laptop.
Direct talks between the negotiators
The first direct meeting between the delegations in Switzerland lasted around an hour on Sunday afternoon, according to reports.
The US delegation was led by Vance, who had earlier indicated that he expected to return to the US on Monday.
On the Iranian side, Araghchi and Parliament Speaker Mohammad Bagher Ghalibaf were among those taking part as negotiators.
The US and Israel began the war with Iran in late February. A ceasefire came into force in early April, though it has been breached sporadically.
Last week, the US and Iran reached a memorandum of understanding aimed at achieving a comprehensive agreement to end the war within 60 days.
