Donald Trump has said Iran has “not yet paid a big enough price” despite reviewing a new peace proposal offered by Tehran.

The US president has been touting the possibility of carrying out fresh strikes on Iran, with his efforts to pressure the country’s regime into agreeing a deal favourable for the US having so far failed.

“I will soon be reviewing the plan Iran has just sent to us but can’t imagine that it would be acceptable in that they have not yet paid a big enough price for what they have done to humanity, and the world, over the last 47 years,” he wrote on Truth Social.

He told reporters on Saturday that there was a “possibility” he could order more strikes against Iran, particularly “if they misbehave, if they do something bad”.

Efforts by mediators in Pakistan to bring delegations from the Washington and Tehran back to the negotiating table have been fruitless since a round of talks in Islamabad in April collapsed.

Iranian officials have offered a similarly gloomy forecast for efforts towards peace, warning on Saturday that a renewal of the war was “likely”.

One official said that an Iranian proposal so far rejected by Trump would open shipping in the Strait of Hormuz and end the US blockade of Iran while leaving talks on Iran’s nuclear program for later.

When asked about Iran’s proposal before boarding a flight to Miami at West Palm Beach, Florida, Trump replied: “They told me about the concept of the deal. They’re going to give me the exact wording now.”

Tehran had previously made clear it is prepared to open the Strait of Hormuz.

While saying repeatedly he is in no hurry, Trump is under domestic pressure to break Iran’s hold on the strait, which has blocked passage for 20 per cent of the world’s oil and gas supplies and pushed up energy prices.

Iranian media said Tehran’s 14-point proposal included the withdrawal of U.S. forces from areas surrounding Iran, lifting the blockade, releasing Iran’s frozen assets, payment of compensation, lifting sanctions and ending the war on all fronts, including Lebanon, as well as a new control mechanism for the Strait.

But Washington has repeatedly said it will not end the war, which has led to the deaths of thousands of people, without a deal that prevents Iran from obtaining a nuclear weapon.

The Trump administration hailed this as its primary aim when launching strikes in February in the midst of nuclear talks. Iran says its nuclear program is peaceful.

Speaking on condition of anonymity to discuss confidential diplomacy, the senior Iranian official said Tehran believed its latest proposal to shelve nuclear talks for a later stage was a significant shift aimed at facilitating an agreement.

Under the proposal, the war would end with a guarantee that Israel and the United States would not attack again. Iran would open the strait, and the United States would lift its blockade.

“Under this framework, negotiations over the more complicated nuclear issue have been moved to the final stage to create a more conducive atmosphere,” the official said.