US President Donald Trump has suggested that Doge, the cost-cutting agency Elon Musk helped set up, could be used to hurt the billionaire's companies - as the former allies continue their public dispute over Trump's budget plans.
"Elon may get more subsidy than any human being in history, by far," he wrote on social media. "Perhaps we should have DOGE take a good, hard, look at this? BIG MONEY TO BE SAVED!!!"
The tech billionaire wrote in reply: "I am literally saying CUT IT ALL. Now."
Musk has repeatedly criticised Trump's so-called "big, beautiful bill", suggesting that it undermines the work he undertook to cut government spending.
A row between Trump and Musk first blew up last month, with the pair trading barbs publicly before Musk backtracked on some of his attacks.
Congress is currently voting on Trump's bill. The president's Republican Party holds majorities in both houses, though some lawmakers in the party have voted against it - siding with opposition Democrats.
The proposed legislation includes increased spending for border security, defence and energy production that would be partially offset by controversial cuts to healthcare and food-support programmes.
Musk was in charge of Doge (the Department of Government Efficiency), which has been tasked with finding ways of cutting government spending, until his acrimonious White House departure over the "big, beautiful bill".
Trump has suggested that the dissent from the Tesla and SpaceX owner relates to a part of his bill that would remove incentives to buy electric vehicles, such as those Musk produces.
The president has also threatened to remove government subsidies from which Musk's companies benefit.
"He's upset that he's losing his EV mandate, he's very upset, he could lose a lot more than that, I can tell you that," Trump told reporters on Tuesday morning.
"Doge is the monster that might have to go back and eat Elon. He gets a lot of subsidies," he added.
Musk, however, has argued he is ideologically committed to cutting government spending. If passed, Trump's bill would add an estimated $3.3tn (£2.4tn) to the national debt.
Among a string of posts on his social media platform X while voting took place, Musk shared a graph showing US debt over time with the caption: "When are they going to flatten this curve?"
In another, he wrote: "Every member of Congress who campaigned on reducing government spending and then immediately voted for the biggest debt increase in history should hang their head in shame!"
Musk said he would make sure these lawmakers lost their primary races next year. The billionaire businessman - who spent hundreds of millions of dollars to help Trump's re-election bid last year - has even touted the idea establishing a new party to run against both Republicans and Democrats.
In an apparent response to Trump's claim about EV incentives, Musk reposted a clip from an interview in which he said removing them would see Tesla's "competitive position would improve significantly".