US President Donald Trump has said negotiations with Iran will begin on Monday after he decided to call off what he described as a planned military attack on the country.

Speaking to reporters aboard Air Force One on Sunday, Trump said the talks would begin after allies urged Washington to pursue diplomacy.

“They knew the extent of the attack because they saw it forming. Now what we’re doing is we’re talking to them in the form of a negotiation. It begins tomorrow afternoon, and we’ll see,” Trump said, according to CNN.

Trump said Saudi Arabia, the United Arab Emirates, Qatar and Iran had all urged him to halt the planned strike.

“We’re all set to go, but when the allies asked to call it off, they got us sort of saying, ‘Well, let’s see.’ And the reason they ask is they think there’s a deal,” he said.

“There’s a deal on Hormuz, and then there will be a deal on the nuclear, or you might call it the denuclearization of Iran. I call it the denuclearization of Iran.”

According to CNN, Saudi Crown Prince Mohammed bin Salman also discussed de-escalation with Trump during a telephone call.

However, Iranian state media denied that Tehran had requested the United States to cancel any planned military action.

The semi-official Fars news agency dismissed Trump's claims, posting: “Trump the fool has run out of steam!”