The US military will be ready for a possible attack on Iran from Saturday, senior national security officials have told President Donald Trump, according to multiple US media reports.

Trump has not made a final decision on military action and is discussing the matter with top advisers.

Meanwhile, the White House is assessing risks of escalating regional tensions and the political and military implications of holding back, but the rhetoric has escalated in recent days despite the talks between Washington and Tehran in Geneva.

“Should Iran decide not to make a deal, it may be necessary for the United States to use Diego Garcia, and the airfield located in Fairford, in order to eradicate a potential attack by a highly unstable and dangerous regime,” Trump wrote on Truth Social on Wednesday.

"(Trump) is getting fed up. Some people around him warn him against going to war with Iran, but I think there is 90% chance we see kinetic action in the next few weeks," one Trump adviser told Axios.

Any US military operation would likely be a massive, weeks-long campaign conducted jointly with Israel, sources told US media outlets, and the Trump administration was "closer than most Americans realise" to a major war in the Middle East.

The arrival of aircraft carrier USS Gerald Ford in the eastern Mediterranean in the coming days will be a key factor in determining the timing of possible strikes, according to US officials.

Meanwhile, the Pentagon will temporarily withdraw some personnel from the Middle East to US or Europe within three days ahead of possible US action and potential Iranian retaliation, CBS reported, citing multiple US officials.

Wide gaps remain in Geneva talks

Trump's advisers Jared Kushner and Steve Witkoff met Iranian Foreign Minister Abbas Araghchi for three hours in Geneva on Tuesday. Both sides said the talks made progress but wide gaps remain.

Vice President JD Vance said the negotiations went well in some ways, but Trump had set red lines "that the Iranians are not yet willing to actually acknowledge and work through," Vance told “The Story with Martha MacCallum” programme.

White House spokeswoman Karoline Leavitt said on Wednesday there were "many arguments one can make in favour of a strike against Iran" while stressing Trump prefers diplomacy.

"Iran would be wise to make a deal with President Trump and his administration," she said.