US Secretary of State Marco Rubio on Thursday outlined a series of demands for Iran as a new round of nuclear negotiations was postponed, underscoring widening gaps between Washington and Tehran.

Rubio said Iran must end uranium enrichment, abandon its long-range missile program, and accept American inspectors at its nuclear facilities if there is to be any agreement.

“They have to walk away from sponsoring terrorists, they have to walk away from helping the Houthis in Yemen, they have to walk away from building long-range missiles that have no purpose to exist other than having nuclear weapons, and they have to walk away from enrichment,” Rubio said during an interview with Fox News.

His comments reflect persistent divisions in the ongoing diplomatic efforts to resolve long-standing concerns over Iran's nuclear program, while US President Donald Trump escalates his rhetoric around the negotiations, warning of possible military action should talks collapse.

Iran rejects pressure on enrichment and missile program

Tehran has repeatedly stated that it will not compromise on its sovereign right to enrich uranium or continue its missile development efforts, which it maintains are defensive.

Enrichment is a key component in nuclear energy production, but higher levels can also be used to manufacture nuclear weapons.

Rubio argued that even low levels of enrichment pose a risk, "If you have the ability to enrich at 3.67%, it only takes a few weeks to get to 20%, then 60%, and then the 80 and 90% that you need for a weapon."

Iran insists its program is peaceful and compliant with the nuclear Non-Proliferation Treaty (NPT), under which it claims a legal right to enrich uranium. It has consistently denied any intention to pursue nuclear weapons.

Talks postponed amid growing diplomatic strains

On Thursday, a senior Iranian official told Reuters on Thursday that a planned fourth round of nuclear talks in Rome had been postponed, citing Washington’s stance as the cause.

A new date will be considered "depending on the US approach," the official said.

The delay comes amid heightened tensions, with both sides refusing to concede on critical sticking points. While Rubio called for full access to all Iranian nuclear facilities, including military sites, Tehran historically opposed such intrusive measures, especially from American personnel.

Trump has threatened to bomb Iran if a deal is not reached, escalating concerns about potential conflict in the region. Rubio echoed this uncompromising tone by asserting that any meaningful deal must include Iran's acceptance of American inspectors and total transparency.

As diplomatic efforts stall and rhetoric intensifies, the future of the nuclear negotiations remains uncertain. With Tehran resisting the US's unilateral demands, and Washington upping its threats, the prospect for a breakthrough appears remote in the near term.

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