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Tehran threatened on Tuesday that it could enrich uranium to weapons-grade 90% if the US resumes military strikes, as the ceasefire came under strain following US President Donald Trump’s rejection of Iran’s latest peace proposal as “completely unacceptable”.
Ebrahim Rezaei, MP for Dashtestan and spokesperson for the Iranian parliament’s National Security and Foreign Policy Committee, posted the warning on X, saying the option would be discussed in parliament.
Iran’s parliament speaker Mohammad Bagher Ghalibaf separately issued an ultimatum overnight on Tuesday, saying Washington had “no alternative” but to accept Tehran’s rights as set out in its 14-point proposal, or face failure.
Trump has since described the ceasefire as being on “massive life support,” after Iran’s foreign ministry called US demands “unreasonable”. Trump met with his national security team on Monday to discuss the possibility of renewed strikes on Iran, according to US media reports.
Meanwhile, Israeli media reported that some Israeli citizens had received threatening text messages purportedly sent by Iran, warning that they would “see the sun in the night skies” — a phrase interpreted as referring to possible Iranian missile or drone strikes.
Uranium enrichment core issue
The nuclear question remains the central obstacle. Iran holds roughly 400 kilograms of enriched uranium — enriched to 60%, just below the 90% threshold for weapons-grade material — which Washington regards as a core concern.
Iran has said its right to enrich uranium is non-negotiable, although it has indicated the level of enrichment is open for discussion.
Trump has repeatedly said Iran will not be permitted to obtain a nuclear weapon under any circumstances. The US position is that Iran must either transfer its enriched uranium stockpiles abroad or halt enrichment for at least 20 years.
Trump’s special envoy Steve Witkoff told Fox News that Iranian negotiators had told him and Jared Kushner in earlier talks that Iran held around 460 kilograms of uranium enriched to 60%, which could be upgraded to weapons-grade material within one to two weeks. That amount, Witkoff said, would be sufficient to produce around 11 nuclear warheads.
Trump said Iranian officials had verbally agreed to the removal of enriched uranium from a site he described as having been obliterated by US strikes, but that the commitment was absent from the written proposal subsequently sent to Washington.
Israeli Prime Minister Benjamin Netanyahu has insisted the war with Iran cannot be considered over until its nuclear capabilities are eliminated. Asked in a CBS News interview how Iran’s uranium stockpiles could be removed, he said they would need to be retrieved physically on the ground.
The 2015 nuclear agreement — the Joint Comprehensive Plan of Action, or JCPOA — had capped Iranian enrichment at 3.67% and limited stockpiles to 300 kilograms for 15 years.
Trump withdrew the US from the deal in 2018 during his first term, triggering a gradual Iranian rollback. Iran raised enrichment first to 20%, then beyond 60%, drawing repeated warnings from the IAEA.
Following the US and Israeli strikes in June 2025 and in the opening salvo of the war in February, Trump said Iran’s nuclear facilities had been “obliterated,” although satellite imagery of the Natanz complex published in March showed no new damage to the facility or its tunnels.
The ceasefire took effect on 8 April through Pakistani mediation after 39 days of US and Israeli strikes on Iran that began on 28 February.
Talks in Islamabad subsequently failed to produce a lasting agreement, and Trump extended the truce without setting a deadline. Iran delivered its response to a US proposal via Pakistani mediation on Sunday.