NEW YORK -- US President Donald Trump and billionaire Elon Musk traded barbs over the Trump administration's sweeping tax-cut and spending bill on Thursday, a week after Musk left the administration.

The tax-cut and spending bill, also known as the "Big and Beautiful Bill," is part of Trump's core agenda and includes a series of economic measures such as eliminating tax credits for electric vehicle consumers, increasing investment in border security, and lowering corporate and personal tax rates.

Musk has been fiercely criticizing the bill in recent days. On Thursday, he called the bill a "mountain of disgusting pork" on social media.

"In the entire history of civilization, there has never been legislation that (is) both big and beautiful. Everyone knows this," said Musk on social media.

"Either you get a big and ugly bill or a slim and beautiful bill. Slim and beautiful is the way," he said.

Trump said Musk's dissatisfaction stemmed from the bill's proposal to eliminate tax credits for electric vehicle consumers, which affected Musk's interests as CEO of electric vehicle manufacturer Tesla.

"Look, Elon and I had a great relationship. I don't know if we will anymore," Trump said in the Oval Office.

"I'm very disappointed in Elon. I've helped Elon a lot," he added.

"Without me, Trump would have lost the election, Dems would control the House and the Republicans would be 51-49 in the Senate," said Musk at one point on Thursday afternoon.

As for Trump's post saying Musk "wearing thin" and going "crazy" and he asked Musk to leave, Musk referred the post as "Such an obvious lie. So sad."

Musk, however, said he opposed the bill because it would increase the federal deficit.

Following Trump's criticism of Musk, Tesla's stock price fell more than 15 percent on Thursday afternoon. As of this year, Tesla's share price has fallen over 30 percent.

Musk was once a staunch ally of Trump, spending nearly 300 million U.S. dollars to support Trump's campaign in 2024. After Trump won the presidential election, Musk joined the newly established Department of Government Efficiency (DOGE), responsible for overseeing bureaucratic corruption and reducing the national debt.

DOGE's work led to thousands of federal government layoffs and cuts of billions of dollars in foreign aid and other programs, sparking multiple protests in the United States and around the world. On Wednesday last week, Musk announced his departure.

Musk also initiated a survey on Twitter regarding "is it time to create a new political party in America that actually represents the 80 percent in the middle," which drew more than 510,000 votes in about one hour.