Washington (AFP) - Elon Musk has had a series of angry social media dust-ups with Wall Street analysts, journalists, employees and others.

But his latest outburst on Twitter attacking a British rescue worker in Thailand has raised fresh concerns over the star tech entrepreneur's stability and leadership abilities.

Musk, the South African-born innovator and billionaire behind Tesla and SpaceX, found himself in hot water after insulting Vern Unsworth, a British diver who worked on the Thai soccer team rescue and who dismissed Musk's plan to recover the trapped group.

The since-deleted weekend tweet referred to Unsworth as "pedo guy," an apparent reference to pedophilia, faced a deluge of criticism on social media and from analysts questioning whether Musk had crossed a line on responsible conduct for a CEO.

"This is the most brand-damaging thing Elon Musk has ever done," said Roger Kay, analyst with Endpoint Technologies Associates who follows the technology sector.

Kay said Musk appeared to be following in the footsteps of President Donald Trump in using Twitter to vent frustration and insult anyone with whom he disagrees.

"It's totally gratuitous. It wasn't necessary," Kay said of the Musk insult to the Briton, who has threatened a lawsuit. "It makes him very Trump-like."

Tesla shares skidded 2.75 percent to close at $310.10 following the latest controversy, adding to pressure on the electric automaker which has struggled to meet production targets for its Model 3, seen as crucial to its long-term viability.

- Pressure fractures -

Musk "is under a lot of pressure and we're seeing pressure fractures," Kay said.

"He's been sleeping in his factories trying to get production up and that's been difficult. But when he talks to investors, he has to reassure them that all that money isn't going to fall on the floor."

Musk has cultivated reputation as a creative genius, with some comparisons to another technology star known for being erratic, the late Apple-co-founder Steve Jobs.

Patrick Moorhead, analyst and consultant with Moor Insights & Strategy, said there were "some similarities up to this point" between Musk and Jobs, but that the latest personal insult appeared to cross a line.

"Steve jobs didn't take it to this extent," Moorhead said.

To avoid long-term damage, "the first thing Musk needs to do is issue a huge apology," Moorhead said.

The analyst said the boards of Tesla and privately held SpaceX need to assert themselves in this situation to ensure Musk does not go off the rails.