Iran's Supreme Leader, Ayatollah Ali Khamenei, definitively rejected the US proposal to reach an agreement on Iran's nuclear programme, asserting that the country will continue uranium enrichment.

Speaking on June 4 at the expansive mausoleum of Ruhollah Khomeini in southern Tehran, the founder of the Islamic Republic, Khamenei lambasted the American plan.

“National independence means that the country should not wait for the green or red light from the United States and its ilk; a key element of national independence is the principle of 'we can'," Ayatollah Khamenei said. “In the nuclear issue, the US plan is 100% against ‘we can'," he added.

Khamenei stressed that the nuclear industry extends beyond mere energy production, describing it as a "parent industry" for which uranium enrichment is "key." He claimed this fundamental importance is precisely why Iran's adversaries have targeted enrichment.

The rejection follows five rounds of indirect talks between Iran and the US on the nuclear issue, mediated by Oman. Last week, Oman's foreign minister delivered the US proposal, which outlined Washington's terms for an agreement.

Conflicting reports had emerged regarding the US offer, with some suggesting it permitted Iran to enrich uranium at low levels. However, US President Donald Trump clarified on his Truth Social account that any potential agreement would explicitly forbid uranium enrichment.

Khamenei sharply criticised the US administration's stance, declaring, "Our response to the US nonsense is clear: they cannot do anything about this."

He accused the US of seeking to prevent Iran from developing its own nuclear industry to maintain Iranian dependence. "Why are you interfering with whether Iran has enrichment or not? What does it have to do with you? Who are you?" he demanded.

US officials have consistently maintained that Iran is permitted to import uranium for civilian purposes but not to enrich it domestically. The United States and Western nations have expressed significant concern that Iran's accumulating uranium stockpile could be used to construct a nuclear weapon, an accusation Tehran vehemently denies.

Notably, Iran is the only non-nuclear weapon state in the world to enrich uranium to 60%, a level alarmingly close to the 90% purity required for weapons-grade material. Iran contends that these measures are a direct response to the US withdrawal from the 2015 nuclear deal and the subsequent re-imposition of stringent sanctions.

According to the latest report from the International Atomic Energy Agency (IAEA), as of May 17, Iran has stockpiled 408.6kg of uranium enriched to 60%. This represents a substantial increase of nearly 134kg, or approximately 50%, compared to the previous report in February.

The Supreme Leader's latest rejection comes as Iranian Foreign Minister Abbas Araghchi had earlier indicated that Tehran was "considering and responding" to Washington's written offer, delivered via Oman by chief US negotiator Steve Witkoff.

A day earlier, White House press secretary Carolyn Levitt informed reporters that "Witkoff has made a detailed and acceptable offer to the Iranian regime that the president hopes they will accept. Otherwise, they will face serious consequences."

Trump has repeatedly stated his aim to secure a deal preventing Iran from acquiring a nuclear weapon, warning of "secondary sanctions" and even "bombing" if Iran fails to comply.