Elon Musk has called President Donald Trump's trade adviser, Peter Navarro, a "moron" over comments he made about his electric vehicle firm, Tesla.

Musk - who is also a member of the Trump administration - said Navarro was "dumber than a sack of bricks" in posts on his social media platform X.

It was in response to an interview Navarro gave in which he criticised Musk. "[He's] not a car manufacturer. He's a car assembler, in many cases," Navarro said.

Navarro was being interviewed about Trump's sweeping tariff policy and said he wanted to see parts made in the US in the future instead.

Musk, who has hinted at his opposition to White House trade policy, said Navarro's claims about Tesla were "demonstrably false".

The spat was the most public sign of disagreement yet between Trump's trade team and Musk, the world's richest man, who heads the Department of Government Efficiency (Doge), which is tasked with slashing the size and spending of the federal government.

Later on Tuesday, White House spokeswoman Karoline Leavitt was asked about the row between Musk and Navarro. "These are obviously two individuals who have very different views on trade and on tariffs," she told reporters.

"Boys will be boys, and we will let their public sparring continue," Leavitt said.

Trump has in part justified his global wave of tariffs by saying he wants to revive manufacturing in the US. This is an argument Navarro made during an appearance on CNBC on Monday.

"If you look at our auto industry, right, we're an assembly line for German engines and transmissions right now," he said.

"We're going to get to a place where America makes stuff again, real wages are going to be up, profits are going to be up," Navarro added.

Responding to the comments on Tuesday, Musk posted a link to a 2023 article by car valuation firm Kelley Blue Book, which cited Cars.com findings that Tesla vehicles had the most parts produced in the US.

"By any definition whatsoever, Tesla is the most vertically integrated auto manufacturer in America with the highest percentage of US content," Musk wrote in a follow-up post.

Technology industry analyst Dan Ives said the company was less exposed to tariffs than other US car makers such as GM, Ford, and Stellantis.

But he too, claimed the company sourced the majority of its parts from outside the US, particularly China.

"The tariffs in their current form will disrupt Tesla, the overall supply chain, and its global footprint which has been a clear advantage over the years vs. rising competitors like BYD," he said.

Jeffrey Sonnenfeld, a dean and professor at the Yale School of Management who hosted a gathering of business executives in Washington last month, said Musk was articulating what many American CEOs think but are reluctant to say publicly about Trump's trade policies.

"Seventy-nine percent of them said they're embarrassed in front of international partners, and 89 percent said this is needlessly taking us into a recession and a misguided economic policy," Mr Sonnenfeld told the BBC, referring to a survey taken at the event he hosted.

Even before the row with Navarro, Musk had hinted at his dissatisfaction with the tariff policy.

On Monday, he posted a video of the economist Milton Friedman, a noted opponent of tariffs, in which he extols the values of the free market.

Trump's tariffs have caused stock market falls around the world, as investors calculate it will result in firms making smaller profits.

Musk said in an X post on 27 March that even his company would not be immune from tariff disruption.

Another Trump backer, the billionaire fund manager Bill Ackman, has called for a pause on the tariffs to stave off what he called "major global economic disruption".

In a post on X, he said the current plans would do "unnecessary harm."

Navarro is considered an ultra-Trump loyalist and was jailed for ignoring a subpoena from a House committee investigating alleged efforts to overturn the 2020 election.

He is thought to be one of the main architects of Trump's tariff policy.