New negotiations between the United States and Iran are expected to begin Monday after President Donald Trump opted not to proceed with what he called planned large-scale military strikes against Iran.

Speaking to reporters on Air Force One on Sunday, Trump said diplomatic talks were progressing. “We’re talking to them in the form of a negotiation. “It starts tomorrow afternoon,” he said.

Earlier on his Truth Social platform, Trump said Iran and some US partners in the Middle East had asked Washington to postpone military action because the outlines of an agreement had been reached.

Iran has not officially said Trump’s story is true. Tehran has said any talks would be conditional on its terms and has challenged several of Trump’s recent statements.

Trump would not provide any details about the location of the talks or who would be involved. Nor did he set a deadline for reaching an agreement.

We'll see how it goes. Trump said he preferred a diplomatic solution to military action, adding: “We’re ready to go anytime we want to go.”

The US president said officials from the United Arab Emirates and Qatar and Saudi Crown Prince Mohammed bin Salman had urged Washington to hold off on military action because they believed there was a chance for negotiations to succeed.

Trump also hinted at ongoing discussions about the Strait of Hormuz and Iran’s nuclear programme, but he did not provide further details.

Financial markets responded positively to the prospect of a new diplomatic push. Brent crude fell about 4.5% to $83.98 a barrel on Monday in Asia trading, while West Texas Intermediate crude declined about 4.6% to $80.74.

Since the escalation of fighting between Iran and its foes on February 28, energy markets have been tumultuous. The Strait of Hormuz is a vital global shipping route, transporting about a fifth of the world’s crude oil and liquefied natural gas supplies.

Trump said Tehran had asked the United States to wait to take military action, a statement Iran's semi-official Mehr News Agency said was false.

Iranian media quoted Iranian Foreign Minister Abbas Araghchi on Sunday as saying that Oman-mediated talks over the Strait of Hormuz were heading towards a possible end.

Trump also called the aborted operation “the biggest hit since World War II" but provided no evidence to support that characterisation.

Trump was asked whether planned strikes would have targeted Iran’s energy infrastructure, but he did not answer. International law experts have previously warned that attacks on civilian energy facilities could raise issues under international humanitarian law, depending on the circumstances.

Iran's acting defence minister, Majid Ibn al-Reza, said Tehran still considered military threats from its foes credible, regardless of whether they were aimed at psychological pressure.

The latest comments continue a pattern of Trump switching back and forth between warnings of military action and expressing support for diplomacy. The president has spoken before of possible force and also said repeatedly that negotiations were still possible.

Polls of public opinion in the United States have also shown increasing anxiety about the economic and political costs of the conflict. Some Republican strategists have reportedly worried that the issue could influence voter sentiment ahead of the midterm elections in November.