US President Donald Trump on Sunday signalled cautious optimism over ongoing negotiations with Iran, saying he had instructed American representatives “not to rush into a deal”, even as reports suggested that a broad framework for an agreement had already been negotiated.

The proposed agreement, if finalised, is expected to pave the way for reopening the Strait of Hormuz, ease global energy supply concerns and address Tehran’s stockpile of highly enriched uranium.

In a post on his social media platform Truth Social, Trump described the talks as “constructive” and said negotiations were “proceeding in an orderly and constructive manner”. He added that ties with Iran were becoming “much more professional and productive”.

Trump also sought to counter criticism from hardline Republicans pressing for a more aggressive stance against Tehran. “Both sides must take their time and get it right,” he wrote.

The Strait of Hormuz, a crucial global energy transit route, has remained effectively shut since the US and Israel launched strikes on Iran on February 28. The disruption triggered sharp increases in oil and gas prices and raised concerns over prolonged instability in global energy markets.

Washington has maintained a blockade on Iranian shipping routes for more than a month. Trump said the blockade “will remain in full force and effect until an agreement is reached, certified, and signed”.

Marco Rubio warns if negotiations failed with Iran

US Secretary of State Marco Rubio on Monday said Washington remained committed to diplomacy but warned that the US had other options if negotiations failed.

Speaking to reporters in New Delhi, Rubio said the United States would give diplomacy every opportunity to succeed before considering “alternatives”.

“There was a pretty solid thing on the table in terms of their ability to open up the strait, get the strait open, enter into a very real, significant, time-limited negotiation on the nuclear matter, and hopefully we can pull it off,” Rubio said.

Uranium stockpile at centre of negotiations

One of the key elements under discussion is Iran’s agreement to surrender its stockpile of highly enriched uranium. Part of the material may be diluted while the remainder could be transferred to a third country, with Russia reportedly offering to take custody.

Accorring to media reports, US anctions relief would depend on Tehran giving up the uranium reserves. Iran currently possesses 440.9 kilograms of uranium enriched up to 60% purity, according to the International Atomic Energy Agency, bringing it technically close to weapons-grade levels.

Tehran, however, has not publicly committed to surrendering its uranium stockpile. Iranian authorities continue to insist that their nuclear programme is peaceful and maintain that the country has the right to pursue nuclear technology.