Tech billionaire Elon Musk has blasted Donald Trump's top trade adviser as a "moron" and "dumber than a sack of bricks", escalating a war of words within the US president's inner sanctum over his tariff policy.
It came as US markets swung wildly again on Tuesday, local time, after initially being buoyed by fresh signs the president was willing to negotiate over his sweeping tariff agenda.
Peter Navarro, who is the senior counsellor to Mr Trump on trade and manufacturing, is considered one of the most ardent supporters of keeping tariffs in place for the long term.
But his full-throated support for tariffs on many of America's biggest trading partners has angered Mr Musk, who earlier this week began posting online about the virtues of free trade.
In an interview on Monday, Mr Navarro responded to Mr Musk's implied criticism by labelling the billionaire a "car manufacturer" who imported cheap parts for his Tesla vehicles from overseas.
"He's a car assembler in many cases — if you go to his Texas plant, a good part of the engines that he gets … the batteries come from Japan and come from China, the electronics come from Taiwan," he told CNBC.
Responding to the clip on his social media platform X, Mr Musk said Mr Navarro was "truly a moron".
"What he says here is demonstrably false," he added.
"Tesla has the most American-made cars.
"Navarro is dumber than a sack of bricks."
Responding to the public spat, White House press secretary Karoline Leavitt said: "Boys will be boys."
"We will let their public sparring continue. And you guys should all be very grateful that we have the most transparent administration in history," she said.
"And I think it also speaks to the president's willingness to hear from all sides that he has people at the highest levels of this government, in this White House, who have very diverse opinions on very diverse issues."
The feud between Mr Musk and one of Mr Trump's most senior confidants has been rumbling for days, with the tech billionaire appearing to publicly break with the Trump administration's embrace of protectionism.
Last week, Mr Musk called for Europe and the US to move towards a "zero-tariff situation" during a videolink interview with the Italian deputy prime minister.
Markets listening for signs of deals
After three days of global market turmoil, American stocks regained some lost ground in early trading on Tuesday, amid indications the Trump administration was open to negotiating deals over tariffs. The S&P 500 index initially looked set for its best day in years after gaining more than 4 per cent.
But the markets plummeted again later in the day, and the S&P 500 closed 1.6 per cent lower, taking its total losses close to 20 per cent since it peaked in February.
Markets in the US, Europe and Asia have all been falling in the days since Mr Trump's announcement of a blanket 10 per cent tariff on all American imports, as well as significantly higher rates on goods from dozens of other countries seen as "the worst offenders".
The 10 per cent base tariff took effect over the weekend, with the higher "reciprocal tariffs" due to come into effect on Wednesday.
At the same time, tariffs on Chinese imports are set to shoot up to 104 per cent unless Beijing drops its retaliatory duties on US goods by midnight on Tuesday.
While White House officials had initially poured cold water on the idea of doing deals with trading partners, saying, "This is not a negotiation, this is a national emergency," but they are increasingly signalling a willingness to do just that.
On Tuesday, US Treasury Secretary Scott Bessent said 70 countries had reached out to the White House for talks.
"I think you are going to see some very large countries with large trade deficits come forward very quickly," Mr Bessent told business network CNBC.
"If they come to the table with solid proposals, I think we can end up with some good deals."
US trade representative Jamieson Greer told the Senate Finance Committee that the number of countries offering to negotiate proved the president's strategy was "already bearing fruit".
Japan and South Korea, two of the US's closest Asian allies, are among the first to win audiences with top Trump officials for post-tariff talks.
Mr Bessent announced on X he would lead trade negotiations with Japanese Prime Minister Shigeru Ishiba, whose country faces a 24 per cent levy.
Mr Trump then announced he had spoken with South Korea's acting president about trade and tariffs, and that officials from that country were heading to the US for talks.
"We have the confines and probability of a great DEAL for both countries. Their top TEAM is on a plane heading to the US, and thing are looking good," he posted on Truth Social.
Trump official faces heat over treatment of Australia
Tensions flared at the Senate hearing as Mr Greer was questioned over the 10 per cent tariff imposed on Australia.
Mr Greer defended the tariff on Australia, telling the committee the country had the lowest rate available under the scheme but that Australia would not accept American beef and pork imports.
Democratic senator Mark Warner interrupted, yelling over the top of Mr Greer: "We have a trade surplus with Australia, we have a free trade agreement, they are an incredibly important national security partner. Why were they whacked with a tariff?"
Mr Greer responded by saying the Trump administration was trying to deal with America's budget deficit, and added, "We should be running up the score with Australia," — a sporting term that refers to a team continuing to score points even when they are certain of winning.
"They ban our beef, they ban our park, they're getting ready to impose measures on our digital companies," Mr Greer said.
"You're a much smarter person than that answer," Senator Warner responded.
"The idea that we are going to whack friend and foe alike, and particularly friends with this level, is both insulting to Australians, undermines our national security and, frankly, makes us not a good partner."
Last week, Mr Trump also complained about Australia's refusal to accept American beef when he announced details of the tariffs, but Australian officials have since said US beef can be exported to Australia.
