Washington and Tehran have observed a ceasefire since April 8 while mediators push for a negotiated settlement, although Iran has imposed controls on Gulf shipping and the US has blockaded Iran's ports.

On Sunday, during a visit to India, US Secretary of State Marco Rubio told reporters: "I do think perhaps there is the possibility that in the next few hours the world will get some good news."

Trump, however, later said in a social media post: "I have informed my representatives not to rush into a deal in that time is on our side".

"The Blockade will remain in full force and effect until an agreement is reached, certified and signed," he added.

Earlier Trump had posted on social media that the deal "has been largely negotiated, subject to finalisation between the United States of America, the Islamic Republic of Iran and the various other Countries".

Rubio said the agreement would start a "process that can ultimately leave us where the president wants us to be, and that is a world that no longer has to fear or worry about an Iranian nuclear weapon".

Israeli Prime Minister Benjamin Netanyahu said on Sunday that he and Trump had agreed that "any final agreement with Iran must eliminate the nuclear threat entirely".

"President Trump made clear that he will remain steadfast in the negotiations regarding his longstanding demand for the dismantlement of Iran's nuclear programme and the removal of all enriched uranium from Iranian territory, and that he will not sign a final agreement absent these conditions," an Israeli official, speaking on condition of anonymity, told AFP.

- 'Seize this moment' -

European leaders, keen to see Hormuz open and energy prices fall, welcomed the optimism early on Sunday. European Commission President Ursula von der Leyen hailed "progress towards an agreement", while Britain's Prime Minister Keir Starmer vowed to work with "international partners to seize this moment".

Iranian officials confirmed the existence of a draft agreement, but stressed that -- despite the long-standing US demand for an end to its uranium enrichment -- talks on the issue of Iran's contested nuclear programme have been deferred for 60 days after any deal.

Iranian President Masoud Pezeshkian told state television Iran was "still prepared to assure the world that we are not seeking nuclear weapons", but it was unclear if this promise would be enshrined in the text of the deal.

- 'Lasting peace' -

According to Iran's Fars news agency, Washington has agreed to release part of Tehran's funds frozen abroad under international sanctions and to end its naval blockade of ships travelling to and from Iranian ports.

In exchange, "according to this draft, passage through the Strait of Hormuz would return to pre-war levels under Iranian management".

And, Fars said, "sanctions on oil, gas, petrochemicals and their derivatives would be temporarily lifted during the negotiation period so that Iran can freely sell its products".

Prominent Iranian-American academic Vali Nasr said the deal on the table appeared like an Iranian victory, but warned that if Washington gave too much ground this would increase Tehran's suspicions.

"The deal in play looks like a win for Iran. But Tehran is not convinced that it is not a dress rehearsal for war now or in 30 days," he posted on social media.

"In fact, the more generous the terms for Iran the more the suspicion that the US is not serious about peace and wants to distract Iran ahead of another attack. Iran will be focused on evidence of US military backdown."

Leaders from Saudi Arabia, the United Arab Emirates, Qatar, Egypt, Jordan and Bahrain, as well as representatives from Turkey and Pakistan, joined a call with Trump to discuss the deal on Saturday.

Pakistan, which mediated historic face-to-face negotiations between US and Iranian delegations in April, hopes to host another round of talks "very soon", Prime Minister Shehbaz Sharif said.

He said Pakistan's army chief Asim Munir, who visited Tehran on Friday and Saturday, also joined the call, which "provided a useful opportunity... to move the ongoing peace efforts forward to bring lasting peace in the region".

Meanwhile, in a rare public appearance at the Grand Mosalla mosque in Tehran that was covered by state media, Ali Abdollahi, the head of Iran's central military command, struck a defiant tone.

"We are on a war footing and all our armed forces are fully ready, with all their resources and equipment, to confront any enemy," he said.

burs/ris/amj