The United States temporarily suspended sanctions on Iranian oil on Monday after Vice President JD Vance said Iran would let U.N. nuclear inspectors return to the country, following talks in Switzerland.

Last week, Tehran and Washington signed a memorandum of understanding laying the groundwork for the negotiations, after nearly 40 days of fighting that was followed by a shaky and often-broken ceasefire.

Officials said conditions had been set for 60 days of technical talks to begin, again in Switzerland, to secure a long-term settlement.

"We laid a very good foundation for a successful final deal," Vance told reporters at Switzerland's luxury Burgenstock resort, adding that "the final deal is the house ... We haven't built the house, but we've laid a successful foundation to get to a good place for the American people."

Separately, the U.S. Treasury said it was temporarily lifting sanctions on Iran to allow the Islamic Republic to produce, sell and deliver crude oil and related products through Aug. 21.

Treasury Secretary Scott Bessent cited Tehran's commitment in ongoing negotiations to "free and open transit" in the Strait of Hormuz and permission for International Atomic Energy Agency (IAEA) inspectors to enter their country as a reason for pausing the sanctions.

The negotiators aim to tackle some of the most intractable issues that have dogged U.S.-Iranian relations for decades, including Tehran's nuclear programme.

Iranian foreign Ministry spokesman Esmaeil Baqaei said on Monday that "a very brief discussion took place regarding the nuclear issue, but there was no discussion of details" and that nuclear talks had not begun.

Vance, meanwhile, said Tehran had agreed to invite IAEA inspectors "back to their country", calling it "a major milestone... and the first step in permanently denuclearising" Iran.

Tehran suspended some cooperation and blocked inspectors from the agency accessing key nuclear sites bombed by the U.S. and Israel in 2025's 12-day war, but inspectors continued to visit Iran, last doing so in November.

Iran was yet to comment on Vance's statement on Monday.

As part of the deal, Tehran is set to get some form of sanctions relief from Washington, as well as the unfreezing of assets.

Vance insisted that assets had not yet been unfrozen and that, if they were, they would be used to buy U.S. goods such as soy beans and would not fund terrorism.

He called it "a classic Trump deal, where if Iranian assets are ever unfrozen, they're going to go to make American farmers richer and to feed the Iranian people."

Shortly after, the U.S. said it was lifting sanctions on Iranian oil sales until August 21.

In the weeks and days before the U.S.-Iran talks, the war in Lebanon between Israel and Iran's close ally Hezbollah has threatened to collapse the ceasefire, though the country has been relatively calm since Sunday.

Israeli leaders have expressed deep misgivings over the deal signed last week and have insisted that their troops will continue to occupy southern Lebanon and are free to respond to any threats there.

Tehran and Washington, meanwhile, have set up communication lines to end the fighting in Lebanon and to keep the vital Strait of Hormuz open, mediators said.

Iran closed the strait, through which much of the world's oil and gas travels in peacetime, early in the war, sending economic shockwaves across the globe.

Before the conflict began, there was free international passage through the strait, but Tehran appears keen to monetise the waterway as part of any deal.

Tracking data on Monday showed vessels were still transiting the straits, despite Iran saying on Saturday it had closed the strait again over Israeli attacks in Lebanon.

Details of last week's deal and what was agreed on Sunday remain scarce, but 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.

"Encouraging progress has been made," they said, including a contact channel set up to "avoid incidents and miscommunication" in 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.

Iran's Foreign Minister Abbas Araghchi, meanwhile, posted on social media: "Oil and petrochem exports are waived, blockade lifted, some frozen assets released, and major reconstruction & development plan launched for Iran."

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

By Monday afternoon, there had been no reports of Israeli strikes or continued fighting, with some residents of southern Lebanon cautiously trickling back to their homes.

Israel's military chief Lieutenant General Eyal Zamir visited troops in south Lebanon on Sunday, where he said Hezbollah was in a "very difficult position" and the army was ready to prevent it from rebuilding its strength.

The overall death toll from the fighting in Lebanon has now surpassed 4,100, the health ministry said.

Lebanon aside, there has been no indication that Iran's support for armed groups across the region, which has long drawn the ire of the US and Israel, will be addressed in the negotiations.