WASHINGTON (Reuters) -U.S. President Donald Trump is not interested in talking with his former ally Elon Musk, amid a bitter feud over the president's sweeping tax-cut bill, a White House official said on Friday, adding that no phone call between the two men is planned for the day. 

A separate White House official had said earlier that Trump and Musk were going to talk to each other on Friday. 

Trump, the world's most powerful leader, and Musk, the world's richest man, conducted an extraordinary day of hostilities on Thursday - largely over social media - marking a stark end to a close alliance.

Shares in Musk's Tesla closed down 14% on Thursday, losing about $150 billion in market value in the largest single-day decline in value in the electric vehicle maker's history. In pre-market trading on Friday they pared some of those losses, rising as much as 5% after the early news that the two men were scheduled to speak. 

Musk had bankrolled a large part of Trump's presidential campaign and was then brought as one of the president's most visible advisers, heading up a sweeping and controversial effort to downsize the federal workforce and slash spending.

The verbal punches erupted on Thursday after Trump criticized Musk in the Oval Office and the pair then traded barbs on their social media platforms: Trump's Truth Social and Musk's X. 

The falling-out had begun brewing days ago when Musk, who left his role as head of the Department of Government Efficiency a week ago, denounced Trump's sweeping tax-cut and spending bill.

The president initially stayed quiet while Musk campaigned to torpedo the bill, saying it would add too much to the nation's $36.2 trillion in debt.

Trump broke his silence on Thursday, telling reporters he was "very disappointed" in Musk.

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

As Trump spoke, Musk responded on X.

"Without me, Trump would have lost the election," wrote Musk, who spent nearly $300 million backing Trump and other Republicans in last year's election.

In another post, Musk asserted that Trump's signature import tariffs would push the U.S. into a recession later this year.

"The easiest way to save money in our Budget, Billions and Billions of Dollars, is to terminate Elon's Governmental Subsidies and Contracts," Trump posted.

Minutes after the closing bell, Musk replied, "Yes," to a post on X saying Trump should be impeached, something that would be highly unlikely given Trump's Republicans hold majorities in both chambers of Congress.

SPACE BUSINESS

Musk's businesses also include rocket company and government contractor SpaceX and its satellite unit Starlink.

Musk, whose space business plays a critical role in the U.S. government's space program, said on Thursday that as a result of Trump's threats he would begin decommissioning SpaceX's Dragon spacecraft. Dragon is the only U.S. spacecraft capable of sending astronauts to the International Space Station. 

Late in the day, Musk backed off the threat. 

In another sign of a possible detente to come, Musk subsequently wrote: "You're not wrong," in response to billionaire investor Bill Ackman saying Trump and Musk should make peace. 

Trump and Musk are both political fighters with a penchant for using social media to attack their perceived enemies, and many observers had predicted a falling-out.

Musk hit at the heart of Trump's agenda earlier this week when he targeted what Trump has named his "big, beautiful bill", calling it a "disgusting abomination" that would deepen the federal deficit. 

His attacks amplified a rift within the Republican Party that could threaten the bill's prospects in the Senate.

Nonpartisan analysts say Trump's bill could add $2.4 trillion to $5 trillion to the nation's $36.2 trillion in debt.

A prolonged feud between the pair could make it harder for Republicans to keep control of Congress in next year's midterm 

(Additional reporting by Jeff Mason, Joey Roulette, Jarrett Renshaw, Nilutpal Timsina, Chandni Shah and Aditya SoniWriting by Andy Sullivan, Costas Pitas and Susan HeaveyEditing by Scott Malone, Don Durfee, Michael Perry and Frances Kerry)