'Train wreck': president mocks Musk for bankrolling new party

Donald Trump has called Elon Musk's decision to start and bankroll a new US political party "ridiculous" and said his former ally had gone "off the rails", as shares in the tech billionaire's Tesla fell amid investor concerns.

- Richard Luscombe Robert Mackey

"Third parties have never worked, so he can have fun with it but I think it's ridiculous," the president told reporters travelling with him to the White House from his New Jersey golf club on Sunday.

He elaborated in a post on his social media platform, Truth Social. "I am saddened to watch Elon Musk go completely 'off the rails', essentially becoming a TRAIN WRECK over the past five weeks," the president wrote. "He even wants to start a Third Political Party, despite the fact that they have never succeeded in the United States. The one thing Third Parties are good for is the creation of Complete and Total DISRUPTION & CHAOS."

He went on to claim that Musk was motivated by discontent over his plan to end subsidies to promote the purchase of electric vehicles.