Renewed diplomatic efforts to end the war between the United States, Israel and Iran are running into difficulty, as Tehran’s nuclear programme has again become one of the main obstacles to a ceasefire. Washington and Israel cited that programme when they launched the war in February.
Nearly eight months after the fighting began, the war has triggered a global energy crisis, and a lasting ceasefire remains out of reach. The conflict has also spread into a wider regional confrontation, with Yemen now emerging as its latest front.
Why the June memorandum of understanding fell apart
The June memorandum of understanding between Washington and Tehran focused on reopening the Strait of Hormuz, a critical global oil chokepoint. It also stated that Iran “shall not procure or develop nuclear weapons”. However, the two sides failed to agree a comprehensive deal covering the nuclear issue within the 60-day period set out in the document, and analysts said differing readings of its clauses led to its collapse.
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The nuclear question has now returned to the centre of the dispute. Tehran insists that uranium enrichment is a right guaranteed under the Non-Proliferation Treaty, while US President Donald Trump has demanded “zero uranium enrichment”. Israeli Prime Minister Benjamin Netanyahu, Trump’s ally, reiterated on Sunday his pledge to topple the Iranian government, which he said was key to stopping it from developing nuclear weapons.
Earlier this week, US Vice President JD Vance appeared to signal concessions on the nuclear question in order to reach an agreement. Qatar and Pakistan are involved in mediation efforts, but it remains unclear how they can bring the two sides together on enrichment.
What the memorandum says about Iran’s uranium stockpile
The memorandum left the future of Iran’s enriched uranium stockpile to further negotiations. It did, however, name downblending under the supervision of the International Atomic Energy Agency as the minimum approach to resolving the issue. Downblending means mixing highly enriched uranium with lower-enriched material, which makes it far less suitable for rapid conversion into weapons-grade material.
The document allowed Iran to reduce the enrichment of the material inside the country rather than hand it over. It did not, though, specify how much material would be downblended, the target enrichment level, or a detailed timetable for carrying this out. The memorandum said the parties would discuss enrichment and other matters tied to Iran’s nuclear needs “based on a satisfactory framework being agreed upon in the final deal”. That final deal never materialised, as the memorandum expired in mid-August.
Tehran’s conditions as Pakistan’s army chief visits
Pakistan’s army chief, Asim Munir, who is also a key negotiator in the conflict, is currently in Tehran. On Tuesday he met Iran’s security chief, Mohsen Rezaei, who said “even a particle of enriched uranium will not exit Iran at all”. Comments carried by Iran’s semi-official Fars news agency described the material as a major national asset that would stay in the country for domestic use.
Rezaei’s remarks came amid media reports that the US wants Iran to move part of its enriched uranium abroad. Trump has previously demanded that the stockpile be removed from Iran. Rezaei also said negotiations with Washington would not start until the US carried out trust-building steps, including meeting the latest conditions set by Tehran.
According to the source, those terms include lifting the US naval blockade of Iranian ports, waiving sanctions and releasing frozen Iranian assets. In return, Iran has offered to reopen the Strait of Hormuz. Another Iranian lawmaker, Alaeddin Boroujerdi, who sits on the parliament’s National Security and Foreign Policy Committee, said Iran was not seeking to produce nuclear weapons. “Iran’s enrichment activities are unrelated to the US, and Washington should focus on fulfilling its own obligations regarding nuclear arms reduction,” he said.
US leaders dig in on enrichment and the nuclear threat
Speaking at a Republican Party campaign rally earlier this week, Trump claimed that US bombing had destroyed Iran’s nuclear facilities and said he would not let Tehran rebuild them. “They cannot have a nuclear weapon,” he told supporters at a rally at Northern Kentucky University.
Vance said earlier this week that the US has “in some ways decisively won” the war and has destroyed the country’s nuclear programme. At a town hall hosted by CBS News, he said Washington was now focused on securing a “long-term” and “verifiable commitment” from Iran not to rebuild its nuclear programme. He questioned whether Iran could rebuild its arsenal or enrichment capacity in the years ahead, pointing to a timeframe of five years.
US Secretary of State Marco Rubio also said this week that the decision to end the war ultimately rests with Trump. “The US will not support any deal that creates a pathway for Iran to have a nuclear weapon. As long as President Trump is in office, they will not have a nuclear weapon,” he said.
Last month, Vance told Reuters that Tehran must make a “meaningful” reduction in its enrichment capacity to meet US demands and bring the war to an end. “If you don’t want a nuclear weapon, then why do you need 60 percent enriched fuel?” he said, adding that Iran should stop producing highly enriched fuel if it wanted to show it was not building a weapon.
Trump’s past claims and an analyst’s view of the talks
The source notes that the Trump administration invoked the imminent threat of Iranian nuclear weapons to launch the war on February 28, 2026. On the first day, US-Israel strikes killed Supreme Leader Ayatollah Ali Khamenei, who had banned the development of nuclear weapons in a fatwa, or religious edict. Trump has often argued that Iran would use a nuclear weapon “within moments after getting it”, and has spoken out against Iran’s nuclear programme many times.
Speaking in Alaska last week, Trump again said he had to start the war because Iran was “two weeks away from having a nuclear weapon.” In April, he had warned that the enriched material would be unearthed and destroyed, and later said the US would bring all of it back to the United States.
Mostafa Najafi, a foreign policy analyst based in Iran, said that despite Washington’s insistence on nuclear negotiations and tangible concessions in that area, the US was “unwilling to offer significant concessions such as lifting sanctions.” In a post on X, he wrote that Washington wants major concessions solely in exchange for lifting the blockade and releasing some of Iran’s assets, adding that for Tehran such steps are no longer a noteworthy concession.
