Elon Musk, the world's richest person and Donald Trump's former adviser, said on Wednesday he regretted some of his recent criticisms of the US president, after the pair's public falling-out last week.

"I regret some of my posts about President @realDonaldTrump last week. They went too far," Musk wrote on his social media platform X, in a message that was received favourably by the White House.

Musk's expression of regret came just days after Trump threatened the tech billionaire with "serious consequences" if he sought to punish Republicans who vote for a controversial spending bill.

Their blistering break-up – largely carried out on social media before a riveted public since Thursday last week – was ignited by Musk's harsh criticism of Trump's so-called "big, beautiful" spending bill, which is currently before Congress.

'Very serious consequences'

Some lawmakers who were against the bill had called on Musk – one of the Republican Party's biggest financial backers in last year's presidential election – to fund primary challenges against Republicans who voted for the legislation.

"He'll have to pay very serious consequences if he does that," Trump, who also branded Musk "disrespectful," told NBC News on Saturday, without specifying what those consequences would be.

Trump also said he had "no" desire to repair his relationship with the South African-born Tesla and SpaceX chief, and that he has "no intention of speaking to him."

But after Musk's expression of regret, White House Press Secretary Karoline Leavitt told reporters that Trump was "appreciative," adding that "no efforts" had been made on a threat by Trump to end some of Musk's government contracts.

Phone call

"The president acknowledged the statement that Elon put out this morning, and he is appreciative of it," Leavitt said.

According to the New York Times, Musk's message followed a phone call to Trump late on Monday night.

Vice President JD Vance and Chief of Staff Susan Wiles had also been working with Musk on how to broker a truce with Trump, the report said.

In his post on Wednesday, Musk did not specify which of his criticisms of Trump had gone "too far."

Musk's stint at DOGE

The former allies had seemed to have cut ties amicably about two weeks ago, with Trump giving Musk a glowing send-off as he left his cost-cutting role at the so-called Department of Government Efficiency (DOGE).

But their relationship cracked within days, with Musk describing the spending bill as an "abomination" that, if passed by Congress, could define Trump's second term in office.

Trump hit back at Musk's comments in an Oval Office diatribe and from there the row detonated, leaving Washington stunned.

Trump later said on his Truth Social platform that cutting billions of dollars in subsidies and contracts to Musk's companies would be the "easiest way" to save the US government money. US media have put the value of the contracts at $18 billion.

Potentially costly fallout

With real political and economic risks to their falling out, both already appeared to inch back from the brink on Friday, with Trump telling reporters "I just wish him well," and Musk responding on X: "Likewise."

Trump had spoken to NBC on Saturday after Musk deleted one of the explosive allegations he had made during their fallout, linking the president with disgraced financier Jeffrey Epstein, who was accused of sex trafficking.