Iran said on Friday that the United States must drop its “excessive demands” to secure an agreement, tempering earlier optimism after talks seen as a last-ditch effort to avert war.

The Oman-mediated negotiations come amid repeated threats from US President Donald Trump to strike Iran and a major American military build-up in the region.

Trump on February 19 gave Tehran 15 days to reach a deal. While Iran insists the talks should focus solely on its nuclear programme, Washington wants curbs on Tehran’s missile programme and its support for militant groups.

The Wall Street Journal reported on Thursday that Trump’s team would demand Iran dismantle its three main nuclear sites and hand over all remaining enriched uranium to the US.

Without detailing the demands he referenced, Iranian Foreign Minister Abbas Araghchi told his Egyptian counterpart that “success in this path requires seriousness and realism from the other side and avoidance of any miscalculation and excessive demands”.

Read: Iran, US hold talks in push to avert war

Following Thursday’s talks in Geneva, Araghchi told state TV the negotiations had “made very good progress and entered into the elements of an agreement very seriously, both in the nuclear field and in the sanctions field”.

Omani Foreign Minister Badr Albusaidi said technical discussions would take place next week in Vienna.

“We have finished the day after significant progress in the negotiation between the United States and Iran,” he wrote on X.

Araghchi, in a separate post, described the latest round as “the most intense so far”.

“It concluded with the mutual understanding that we will continue to engage in a more detailed manner on matters that are essential to any deal — including sanctions termination and nuclear-related steps,” he said.

UN nuclear chief Rafael Grossi also joined the negotiations, a source close to the talks told AFP.

‘Big lies’

Trump, in his State of the Union address, said Iran had “already developed missiles that can threaten Europe and our bases overseas” and was working to build missiles that could soon reach the US.

He accused Tehran of “pursuing sinister nuclear ambitions”, a charge Iran denies, insisting its programme is civilian.

The Iranian foreign ministry dismissed the claims as “big lies”.

On Wednesday, US Secretary of State Marco Rubio said Iran is “not enriching right now, but they’re trying to get to the point where they ultimately can”, adding that Tehran “refuses” to discuss its ballistic missile programme — “and that’s a big problem”.

Iranian President Masoud Pezeshkian said ahead of the talks that the Islamic republic was “not at all” seeking a nuclear weapon.

Read More: Another geopolitical storm

US Vice President JD Vance told The Washington Post there was “no chance” a long-threatened strike on Iran would lead to “a Middle Eastern war for years with no end in sight”.

Military pressure

Parallel to the diplomacy, Washington has mounted a major military build-up, sending the aircraft carrier USS Gerald R. Ford to the Mediterranean.

The US currently has more than a dozen warships in the Middle East, including one aircraft carrier — the USS Abraham Lincoln — nine destroyers and three other combat ships. It is rare for two US carriers to be deployed in the region simultaneously.

Iran says the maximum range of its missiles is 2,000 kilometres. However, the US Congressional Research Service estimates the range could reach about 3,000km — still less than one-third of the distance to the continental US.

A previous round of negotiations collapsed when Israel launched strikes on Iran last June, sparking a 12-day war that briefly drew in the US to bomb Iranian nuclear sites.

Protests have since resumed around Iranian universities.