Stepping up an ongoing verbal clash between the two men, Elon Musk said Donald Trump should “hang up his hat” and is too old to run for the Oval Office in 2024, as a poll shows the former president is losing support among Republican voters.

“I don’t hate the man, but it’s time for Trump to hang up his hat & sail into the sunset,” Musk tweeted late Monday, using the same social media platform that he first tried to buy and is now trying to walk away from. The billionaire businessman’s tweet came after Trump, at a public appearance in Alaska last weekend, called Musk a “bullshit artist” over the Twitter sale.

Musk further tweeted that Democrats – who hold seven of the nine seats on the congressional committee investigating the deadly January 6 attack on the Capitol by Trump’s supporters – “should also call off the attack”.

“Don’t make it so that Trump’s only way to survive is to regain the presidency,” Musk wrote.

Trump would be 78 when the 2024 presidential election is held. If he ignores Musk’s suggestion to hang it up and wins, Trump would be 82 at the end of his second presidential term.

Musk on Friday filed notice to withdraw his $44bn bid to buy Twitter, after the company agreed in late April to sell to him. He argued that the platform had failed to provide promised information on fake and spam accounts, though many observers have noted that tech stocks have plummeted recently, making the sale price look much higher.

It’s unlikely Musk will walk away easily. Twitter said Musk backing out was “invalid and wrongful” and is suing him to enforce a provision in the agreement that may compel him to go through with acquiring the platform, assuming he had the financing for it – which the businessman said in May that he had.

Trump spoke up after Friday’s announcement, saying the Tesla and SpaceX chief’s deal with Twitter was “rotten” anyway.

The Trump-Musk spat has gone on for a while: Musk said he was contemplating supporting Florida’s governor, Ron DeSantis, as the Republican candidate in the 2024 presidential race.

In Alaska, Trump claimed Musk said he’d previously voted for him; Musk has denied it, though he has also criticized Twitter for banning Trump’s account on the platform after the Capitol attack.

If Musk did vote for Trump, he isn’t alone in having a change of heart, a recent poll from the New York Times and Siena College found. Nearly half of Republican party primary voters are interested in supporting someone other than Trump in the 2024 election, and 16% even indicated that if he was the GOP nominee they would support president Joe Biden, vote for a protest candidate, abstain from voting or be unsure of what to do, according to the poll.

That may not sound like much, but that number among Democrats if Biden were to face Trump was 8%, the poll said.