Iran’s Foreign Minister Abbas Araghchi arrived in Geneva ahead of a second round of negotiations between his country and the United States.
Tehran says indirect Iran-US nuclear talks, mediated by Oman, will also be held on Tuesday. Washington is to seek to expand the context of the meeting to include Iran’s ballistic missiles and its vast network of proxies in the region.
Tehran and Washington restarted negotiations this month after previous talks collapsed when Israel and Iran were embroiled in a 12-day conflict in June.
US Secretary of State Marco Rubio told reporters on Monday that he was hopeful the Geneva talks would lead to a deal.
"The president (Donald Trump) always prefers peaceful outcomes and negotiated outcomes to things," Rubio said at a press conference during his visit to Hungary.
Uncertainty surrounds the fate of Iran's stockpile of more than 400 kilogrammes of 60% enriched uranium that was last seen by nuclear watchdog inspectors in June, a small technical step from the 90% enrichment threshold needed for weapons-grade.
Iran’s top diplomat wrote in a post on X that he was meeting with Rafael Grossi, the head of the International Atomic Energy Agency (IAEA), “for deep technical discussion”.
"I am in Geneva with real ideas to achieve a fair and equitable deal. What is not on the table: submission before threats," Araghchi added on X.
Washington said it had dispatched Middle East special envoy Steve Witkoff and Trump’s son-in-law Jared Kushner to Oman for Tuesday’s talks.
IRGC embark on Hormuz war games
The latest talks follow repeated threats from Trump of military action against Tehran, sparked by Iran's deadly crackdown on anti-government protests.
The West believes the programme is aimed at making a bomb, which Tehran has repeatedly denied, claiming it is only for civilian use.
On Friday, Trump suggested that a regime change in Iran would be the "best thing that could happen", after confirming the deployment of a second aircraft carrier group to the Middle East to ratchet up military pressure and enhance the US’ strike force.
Meanwhile, Iran's Islamic Revolutionary Guard Corps (IRGC) began a series of military exercises in the Strait of Hormuz on Monday, state media reported, on the eve of talks with the US.
The war games, whose duration was not specified, aim to prepare the IRGC for "potential security and military threats" in the strait, state-run TV said, after the US deployed a large naval force to the area.
Iranian hardline politicians have repeatedly threatened to block the strait, especially during times of heightened tensions with the United States, but it has never been closed.
The strategic waterway sees about 20% of the world's oil production pass through it.
The exercises, overseen by IRGC chief General Mohammad Pakpour, aim to bolster the Guards' ability to react quickly, Iranian state-run media reported. The IRGC is the ideological arm of Iran's military.
