President Donald Trump said the United States was starting direct, high-level talks with Iran over its nuclear programme on Saturday, in an announcement during a meeting with Israeli Prime Minister Benjamin Netanyahu.
Speaking in the Oval Office at the White House, Mr Trump said he was hopeful of reaching a deal with Iran, but warned that Iran would be in "great danger" if the talks were not successful.
Mr Netanyahu meanwhile said that the US and Israel were working on another deal to free hostages from Gaza, where a ceasefire between Israel and Iran's ally Hamas has collapsed.
"We're dealing with the Iranians, we have a very big meeting on Saturday and we're dealing with them directly," Mr Trump told reporters after a meeting that was meant to focus on Israel's bid to avoid US tariffs.
Mr Trump did not say where the talks would take place, but insisted they would not involve surrogates and would be at "almost the highest level."

Mr Trump's announcement came a day after Iran dismissed direct negotiations on a new deal to curb the Islamic Republic's nuclear programme, calling the idea pointless.
He pulled out of the last deal in 2018, during his first presidency, and there has been widespread speculation that Israel, possibly with US help, might attack Iranian facilities if no new agreement is reached.
Mr Trump issued a stern warning to Iran however.
"I think if the talks aren't successful with Iran, I think Iran's going to be in great danger, and I hate to say it, great danger, because they can't have a nuclear weapon," he said.
Hours before Mr Trump's announcement, Iranian Foreign Ministry spokesperson Esmail Baghaei said Iran was awaiting a US response to Iran's proposal for indirect negotiations.
He said the Islamic Republic believed it was making a generous, responsible and honourable offer.
After Mr Trump spoke, a senior Iranian official, speaking on condition of anonymity, said: "The talks will not be direct ... It will be with Oman's mediation."
Oman, which maintains good relations with both the US and Iran, has been a long time channel for messages between the rival states.
Read more: Netanyahu vows to 'eliminate' US-Israel trade deficit
Iran's Nour news, affiliated with the country's top security body, described Mr Trump's statement about a planned direct meeting as part of a "psychological operation aimed at influencing domestic and international public opinion."
A second Iranian official, speaking on condition of anonymity, said over the weekend, there was possibly a window of around two months to reach a deal, citing worries that Israel might launch its own attack if talks took longer.
The revelation came as Mr Netanyahu became the first foreign leader to personally plead for a reprieve from stinging US tariffs that have shaken the world.
The Israeli Prime Minister pledged that he would "eliminate" the trade deficit between the two countries and also knock down trade "barriers."
His country moved to lift its last remaining tariffs on US imports ahead of the meeting.
Mr Netanyahu said he felt Israel could serve "as a model for many countries" when it came to negotiating on tariffs.
Gaza talks
Mr Netanyahu and Mr Trump also discussed Gaza, where a short-lived, US-brokered truce between Israel and Hamas has collapsed.

Mr Netanyahu said that new negotiations were in the works aimed at freeing more hostages taken by Hamas during its 7 October 2023 attack on Israel, which ignited the war.
"We're working now on another deal that we hope will succeed, and we're committed to getting all the hostages out," Mr Netanyahu said in the Oval Office.
Mr Trump also doubled down on his plan for the US to "control" Gaza - which he described as a "great piece of real estate." He initially announced that plan when Mr Netanyahu last visited him in February.
Earlier, Mr Trump greeted Mr Netanyahu outside the West Wing and pumped his fist, before the two leaders - both wearing dark suits, red ties and white shirts - went inside for a meeting in the Oval Office.
A planned press conference between the two leaders was cancelled at short notice without explanation, in an unusual move - but they spoke to a smaller group of pool reporters at length in the Oval Office.
The Israeli Prime Minister's visit is his second to Mr Trump since the US president returned to power, and comes at short notice - just days after Mr Trump slapped a 17% tariff on Israel in his "Liberation Day" announcement last week.
Mr Trump refused to exempt the top beneficiary of US military aid from his global tariff salvo as he said the United States had a significant trade deficit with Israel.
Mr Netanyahu met with US Commerce Secretary Howard Lutnick and US Trade Representative Jamieson Greer on Sunday night soon after his arrival, according to his office.
The Israeli Prime Minister also met Mr Trump's special Middle East envoy Steve Witkoff yesterday.