Republican White House candidate Donald Trump unveiled a plan Thursday to install tech billionaire Elon Musk at the head of a government efficiency commission to eliminate "trillions" of dollars in wasteful spending.

The Tesla and SpaceX CEO has emerged as a major voice in US politics but is accused of turning the social media platform Twitter, now known as X, into a megaphone for right-wing conspiracy theories since acquiring it in 2022.

Trump told business executives at a speech in New York that Musk -- the world's richest man, according to Forbes -- would oversee a "complete financial and performance audit of the entire federal government" in a second Trump administration.

"As the first order of business, this commission will develop an action plan to totally eliminate fraud and improper payments within six months. This will save trillions of dollars," he said.

The former president is in a knife-edge election race against Democratic Vice President Kamala Harris, who has been setting out her own economic vision ahead of a high-stakes televised presidential debate between the pair on Tuesday.

Trump -- whose administration oversaw an $8.2 trillion rise in the national debt, almost twice as much as President Joe Biden's -- has not publicly identified any of the savings and experts are skeptical about the size of the savings.

'Serving America'

"By definition, this would mean Trump supports cutting Social Security, Medicare, or veterans benefits," Bharat Ramamurti, a former economic official in Joe Biden's White House, posted.

"At the same time, Trump is proposing trillions in tax cuts for the rich. That´'s his fundamental goal: more money for his rich buddies, less for everyone else."

Trump promised sweeping tax cuts, pledged to make the United States the cryptocurrency capital of the world and said he would repeal Biden's Inflation Reduction Act, which lowers costs for clean energy and medication while cracking down on tax cheats.

Musk, who endorsed Trump in July, is one of the Biden-Harris administration's fiercest critics and frequently spreads far-right misinformation about undocumented immigrants and voter fraud.

He resigned from two White House business councils in 2017 -- during Trump's presidency - after the Republican withdrew the United States from the Paris climate agreement.

The efficiency commission was initially Musk's idea, but this is the first time Trump has confirmed he would adopt the plan and tap Musk to lead it.

"I look forward to serving America if the opportunity arises. No pay, no title, no recognition is needed," Musk posted on his social media platform, X.

'Nasty'

As Trump gave his remarks, Harris arrived in the crucial battleground state of Pennsylvania, where she will spend five days preparing for next week's presidential debate.

She does not have campaign events publicly scheduled, and will divide her time between strategizing with advisors, honing her attack lines and taking part in informal meetings with voters.

Harris's entry into the race six weeks ago turbocharged enthusiasm among Democrats who were despondent about Biden's chances against Trump -- but both parties are bracing for a close election on November 5.

Pennsylvania, Georgia and a handful of other swing states are expected to be decisive, and polls show most of those races within the margin of error.

The debate will be the first-ever meeting between Harris and Trump, as the former president refused to attend Biden´s inauguration after falsely claiming he was cheated in the 2020 election.

Harris´s Pennsylvania huddle mirrors Biden´s week-long preparation at Camp David in Maryland for his calamitous June 27 debate with Trump, which effectively ended his presidential campaign.

She has enlisted consultant Karen Dunn, who led debate prep for Barack Obama in 2012 and Hillary Clinton in 2016, as well as consulting for TV political thriller "House of Cards."

Trump, 78, has said he is preparing, as he did against Biden, through speaking engagements on the campaign trail and policy discussions with a tight circle of aides.

During a Fox News interview Wednesday in Pennsylvania, the Republican baselessly accused debate host ABC of bias, called the network and one of its star anchors "nasty," and made unfounded claims that Harris would be shown the debate questions in advance.