US and Iranian officials have made "significant progress" in high-stakes nuclear talks in Geneva, the Omani foreign minister has said, though the chances of a deal that could avert a war remain unclear.

Badr Albusaidi, who acted as mediator, said the two sides planned to resume negotiations "soon" after consultations in their capitals, and technical-level discussions would take place next week in Vienna.

There was no immediate comment from either US or Iranian officials.

With President Donald Trump threatening to strike Iran if there was no deal, this third round of talks in the space of a few weeks was seen as a last-ditch diplomatic effort.

Trump has ordered the largest US military build-up in the Middle East since the US-led invasion of Iraq in 2003, while Iran has vowed to respond to an attack with force.

The president, however, has done little to explain what he is demanding in the negotiations and why there could be the need to take military action now, eight months after the US bombed Iranian nuclear facilities during a war between Israel and Iran.

As in the previous rounds of discussions, the Iranian delegation was led by Foreign Minister Abbas Araghchi, while the US was represented by special envoy Steve Witkoff and Trump's son-in-law, Jared Kushner.

According to Iranian state media, negotiators insisted that Iran had the right to peaceful nuclear energy and rejected US demands to completely stop the enrichment of uranium in Iranian territory and to transfer its stockpile of enriched uranium out of the country.

But officials are believed to have offered concessions, although details have not been made public. In return, Iran expects the lifting of sanctions that have crippled its economy. Opponents of the regime say any relief would give the clerical rulers a lifeline.

It remains unclear which conditions Trump could find acceptable for a deal. Iran has already rejected discussing limits to the country's ballistic missile programme and ending its support for proxies in the region, including Hamas in Gaza, Hezbollah in Lebanon, militias in Iraq, and the Houthis in Yemen.

The indirect talks are taking place at the Omani ambassador's residence in Geneva.

In recent weeks, the US has sent thousands of troops and what Trump has described as an "armada" to the region, including two aircraft carriers along with other warships, as well as fighter jets and refuelling aircraft.

Trump first threatened to bomb Iran last month as security forces brutally repressed anti-government protests, killing thousands of people. But since then, his focus has turned to Iran's nuclear programme, which has been at the centre of a long-running dispute with the West.

For decades, the US and Israel have accused Iran of trying to secretly develop a nuclear weapon. Iran insists its programme is only for peaceful purposes, though the country is the only non-nuclear-armed state to have enriched uranium at near weapons-grade level.

In his State of the Union speech to Congress on Tuesday, Trump briefly and vaguely talked about the tensions with Iran, without clearly laying out the case for strikes.

He said Iran was working to build missiles that would "soon" be capable of reaching the US, without giving details. He also accused the country of trying to "start all over again" with a nuclear weapons programme following last year's strikes, and said he could not allow the "world's number one sponsor of terror... to have a nuclear weapon".

The US struck three nuclear sites in Iran last June, as it joined Israel in its bombing campaign. At the time, Trump said the facilities had been "obliterated". Iran says its enrichment activity stopped after the attacks, although it has not allowed the International Atomic Energy Agency's inspectors to access the damaged sites.

"They want to make a deal," Trump said, "but we haven't heard those secret words: 'We will never have a nuclear weapon'."

Hours before the speech, however, the Iranian foreign minister posted on social media that Iran would "under no circumstances ever develop a nuclear weapon". Araghchi also said there was an "historic opportunity to strike an unprecedented agreement that addresses mutual concerns and achieves mutual interests".

Reacting to Trump's address, an Iranian foreign ministry spokesman accused the US of repeating "big lies" regarding its nuclear programme, ballistic missiles and the number of protesters killed in the crackdown.

The discussions in Geneva could have included the creation of a regional consortium for uranium enrichment, which has been raised in previous negotiations, as well as ideas about what to do with Iran's roughly 400kg (880lb) stockpile of highly enriched uranium and verification and monitoring mechanisms.

What are Trump's options?

Reports in US media, quoting unnamed administration officials, have suggested that Trump was considering an initial strike in the coming days on Iran's Revolutionary Guards or nuclear sites to pressure the country's leaders. If negotiations failed, according to the reports, the president might go as far as ordering a campaign with the aim of toppling the Iranian Supreme Leader, Ayatollah Ali Khamenei.

The Chairman of the Joint Chiefs of Staff is also said to have warned that strikes against Iran could be risky, potentially drawing the US into a prolonged conflict, although Trump has insisted that Gen Dan Caine believes it would be "easily won".

Iran, meanwhile, has threatened to respond to any attack by striking American military assets in the Middle East and Israel.

US-allied countries in the region are concerned that an attack on Iran could lead to a wider conflict, and have warned that air power alone will not be able to change the country's leadership.

Israeli Prime Minister Benjamin Netanyahu, however, has warned against a deal that does not include Iran's ballistic missiles and its proxies. Netanyahu has long described Iran as a key threat for Israel, and a source of instability in the region.

Analysts believe that the prime minister, who visited the White House earlier this month, may be pushing for a campaign with the goal of toppling the Iranian regime.

The US has the world's second-largest nuclear arsenal. Israel is also believed to have nuclear weapons, although it neither confirms nor denies this.

Ahead of the State of the Union, Secretary of State Marco Rubio delivered a classified briefing to the so-called "gang of eight", composed of the leaders of both parties in the Senate and House of Representatives and the chairs and ranking members of the intelligence committees of both chambers.

Following the briefing, Chuck Schumer, the Senate minority leader, gave a brief statement, saying: "This is serious, and the administration has to make its case to the American people." (BBC)

• PHOTO: Omani Foreign Minister Badr Albusaidi said the US and Iran had shown "openness to new and creative ideas" after meeting Jared Kushner and Steve Witkoff. Photo credit: Foreign Ministry of Oman

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