"Let the good times roll", billionaire Elon Musk tweeted on Friday, hours after he completed his acquisition of Twitter for a whopping USD 44 billion and started off as the social media giant's new owner by firing its top executives, including CEO Parag Agrawal.

"The bird is freed," Musk had tweeted on Friday after completing the takeover of Twitter and firing the social media giant's four top executives, including Agrawal, legal executive Vijaya Gadde, Chief Financial Officer Ned Segal and General Counsel Sean Edgett.

"Spoiler Alert. Let the good times roll," Musk, 51, tweeted early Friday morning after ending Thursday night with his acquisition of Twitter.

"I will be digging in more today, Musk said in reply to a tweet by a user called Catturd' who tweeted that he will be tweeting a message "every day to see if anything changes. As of now, I'm still Shadowbanned, ghostbanned, searchbanned, and Twitter removed 1200 followers today - as usual. Nothing has changed - I'll report again tomorrow."

Musk, a self-styled "free speech absolutist", has been critical of Twitter's management and its moderation policies.

"At least one of the executives who was fired was escorted out of Twitter's office, a report in the New York Times reported.

The deal's closing removes a cloud of uncertainty that has hung over Twitter's business, employees and shareholders for much of the year, the CNN commented.

After initially agreeing to buy the company in April, Musk spent months attempting to get out of the deal, first citing concerns about the number of bots on the platform and later allegations raised by a company whistleblower.

Agrawal, 38, was appointed Twitter CEO in November last year after the social media site's co-founder Jack Dorsey had stepped down.

An IIT Bombay and Stanford alumnus, Agrawal had joined Twitter over a decade ago when there were fewer than 1,000 employees at the company.

Agrawal, who was appointed Twitter's chief executive last year, had clashed with Musk publicly and privately in recent months about the takeover, the NYT report said.

Musk also singled out Gadde, 48, criticising her for her role in content moderation decisions at the company , it added.

As the Twitter account of former US President Donald Trump was permanently suspended in January last year, Hyderabad-born Gadde was at the forefront of this dramatic decision undertaken within days of the attempted insurrection by pro-Trump supporters at the US Capitol.

Twitter co-founder Biz Stone thanked Agrawal, Segal and Gadde for their "massive contribution" to the business.

"Thank you to @paraga, @vijaya , and @nedsegal for the collective contribution to Twitter. Massive talents, all, and beautiful humans each!" Stone tweeted.

Musk arrived at the company's headquarters in San Francisco on Wednesday and had been meeting with engineers and advertising executives.

Musk also updated his Twitter description to Chief Twit.

He has promised to transform Twitter by loosening the service's content moderation rules, making its algorithm more transparent and nurturing subscription businesses, as well as laying off employees.

In April, Twitter accepted Musk's proposal to buy the social media service and take it private.

However, Musk soon began sowing doubt about his intentions to follow through with the agreement, alleging that the company failed to adequately disclose the number of spam and fake accounts on the service.

When Musk said he was terminating the deal, Twitter sued the billionaire, alleging he refuses to honour his obligations to Twitter and its stockholders because the deal he signed no longer serves his personal interests.

Earlier in October, Musk said he wanted to pursue his acquisition of Twitter at the original price of USD 54.20 a share if the social messaging service dropped its litigation.

Twitter's lawyers said that the Tesla CEO's proposal is an invitation to further mischief and delay.

A Delaware Chancery Court judge eventually ruled that Musk had until October 28 to cement the Twitter deal or head to trial.

On Thursday, Musk wrote a message to reassure advertisers that social messaging services wouldn't devolve into a free-for-all hellscape, where anything can be said with no consequences!

The reason I acquired Twitter is because it is important to the future of civilization to have a common digital town square, where a wide range of beliefs can be debated in a healthy manner, without resorting to violence, Musk said in the message.

There is currently great danger that social media will splinter into far-right wing and far left-wing echo chambers that generate more hate and divide our society.

The New York Stock Exchange said on Friday that trading in Twitter's shares had been suspending, giving the reason as "merger effective".

Musk's plans for boosting Twitter's value could involve cutting down its workforce, something he's hinted at before. Previous reporting suggested that he'd planned to cut 75 per cent of staff, although he is said to have told Twitter staff this week that's not the case, CNN reported.