Elon Musk, the CEO of Tesla and SpaceX, has tweeted his disapproval of US President Biden's move to end his re-election campaign.
"I believe in an America that maximizes individual freedom and merit. That used to be the Democratic Party, but now the pendulum has swung to the Republican Party," read his post on X, formerly Twitter.
US President Joe Biden ended his re-election campaign on Sunday after fellow Democrats lost confidence in him and his ability to beat Donald Trump, especially after his shockingly poor performance in a televised debate last month against the Republican candidate.
His failure to complete sentences was widely noticed and took away focus from the many false statements and other gaffe made by Mr Trump. Days later he raised fresh concerns in an interview, shrugging off Democrats' worries and a widening gap in opinion polls, and saying he would be fine losing to Trump if he knew he'd "gave it my all."
Mr Biden's gaffes at a NATO summit - invoking Russian President Vladimir Putin's name when he meant Ukrainian President Volodymyr Zelenskiy and calling Harris "Vice President Trump" -further stoked anxieties.
In his note announcing his decision, which he posted on social media, President Biden wrote, "It has been the greatest honor of my life to serve as your President. And while it has been my intention to seek reelection, I believe it is in the best interest of my party and the country for me to stand down and to focus solely on fulfilling my duties as President for the remainder of my term".
The move clears the path for Vice President Kamala Harris to run at the top of the ticket -- the first Black woman to do so in the country's history. It is not clear whether she would be challenged by other party leaders.
(With agencies)