By Parisa Hafezi and Olivia Le Poidevin
GENEVA, Feb 26 (Reuters) - The United States and Iran made significant progress in talks on Thursday aimed at resolving a longstanding nuclear dispute and averting new U.S. strikes, mediator Oman said, amid Washington's large-scale military buildup in the Middle East.
The two sides plan to resume negotiations soon after consultations in their countries' capitals, with techical-level discussions scheduled to take place next week in Vienna, Omani Foreign Minister Sayyid Badr Albusaidi said in a post on X after the day's talks ended in Switzerland.
Any substantial move toward an elusive agreement between longtime foes Washington and Tehran could reduce the imminent prospects for U.S President Donald Trump to carry out a threatened attack on Iran that many fear could escalate into a wider war.
The Omani minister's upbeat assessment followed indirect talks between Iranian Foreign Minister Abbas Araqchi and U.S. envoys Steve Witkoff and Jared Kushner in Geneva, with one session in the morning and the second in the afternoon.
"We have finished the day after significant progress in the negotiation between the United States and Iran," Badr Albusaidi said. But he stopped short of saying the two sides had overcome any of their biggest stumbling blocks to a deal.
Describing the talks as some of the most serious that Iran has had with the U.S., Araqchi told Iranian state television: "We reached agreement on some issues, and there are differences regarding some other issues."
“It was decided that the next round of negotiations will take place soon, in less than a week," he said. The Iranians , he added, had clearly expressed their demand for lifting of U.S. sanctions, which Washington has long insisted will only come after deep concessions from Tehran.
There was no immediate comment from the U.S. negotiating team on the outcome of the talks. But Axios quoted a senior U.S. official as saying the Geneva negotiations were “positive.”
The discussions about the decades-long dispute over Iran's nuclear work come as fears grow of a Middle East conflagration. Trump has repeatedly threatened action if there is no deal, and the U.S. military has amassed its forces in waters near the Islamic Republic.
'INTENSE AND SERIOUS' TALKS
A senior Iranian official told Reuters earlier on Thursday that the U.S. and Iran could reach a framework for a deal if Washington separated "nuclear and non-nuclear issues."
The Trump administration has insisted that Iran's ballistic missile program and its support for armed groups in the region must be part of the negotiations.
After the morning session, Badr Albusaidi said the two sides had exchanged "creative and positive ideas".
But a senior Iranian official said at the time that some gaps still had to be narrowed.
Washington, which believes Tehran seeks the ability to build a nuclear bomb, wants Iran to give up all uranium enrichment, a process that makes fuel for atomic power plants but that can also yield material for a warhead.
Iran has long denied wanting a bomb and said earlier on Thursday it would show flexibility at the talks. Reuters reported on Sunday that Tehran was offering undefined new concessions in return for removal of sanctions and recognition of its right to enrich uranium.
U.S. Secretary of State Marco Rubio said on Wednesday that Iran's refusal to discuss its ballistic missile program was a "big problem" which would have to be addressed eventually.
The missiles were "designed solely to strike America" and pose a threat to regional stability, he said, but offered no proof to back the claim that U.S. territory could be targeted.
TRUMP THREATENS 'REALLY BAD THINGS'
Trump said on February 19 that Iran must make a deal in 10 to 15 days, warning that "really bad things" would otherwise happen.
He briefly laid out his case for a possible attack on Iran in his State of the Union speech on Tuesday, underlining that while he preferred a diplomatic solution, he would not allow Tehran to obtain a nuclear weapon.
In June, the U.S. joined Israel in hitting Iranian nuclear sites and has been ramping up the pressure on Tehran again since January, when Trump threatened to intervene over its crushing of nationwide protests with thousands killed.
Since then, Trump has deployed fighter jets and aircraft carrier strike groups in the region.
Iran responded to last summer's strikes by firing fusillades of missiles at Israel and has threatened to retaliate fiercely if attacked again, raising fears of a wider regional conflict that has alarmed Gulf oil producers.
Within Iran, Supreme Leader Ayatollah Ali Khamenei faces the gravest crisis of his 36-year tenure, with an economy buckling under tightened sanctions and renewed protests following the major unrest and crackdown in January.
President Masoud Pezeshkian said on Thursday that Khamenei has banned weapons of mass destruction, which "clearly means Tehran won't develop nuclear weapons," reiterating a religious decree issued in the early 2000s.
(Reporting by Olivia Le Poidevin and Manuel Ausloos in Geneva; Parisa Hafezi in Dubai; Steve Holland in Washington; Francois Murphy in Vienna; Writing by Olivia Le Poidevin, Michael Georgy, Angus McDowall and Matt Spetalnick; Editing by Stephen Coates, Ros Russell, Timothy Heritage, Andrew Heavens and Cynthia Osterman)
