Elon Musk said Friday that his proposed $44 billion takeover of Twitter were "on hold."

The reason, he tweeted, was a probe into a "calculation that spam/fake accounts do indeed represent less than 5% of users," indicating he's skeptical that the number of inauthentic accounts was that low.

He later added that he was "still committed to acquisition."

Twitter had earlier this month estimated that false or spam accounts represented fewer than 5% of its 229 million monetizable daily active users.

One of Musk's priorities once the dealhas gone through would be to make Twitter "better than ever" by "defeating the spam bots and authenticating all humans."

Stock in Twitter and Tesla swing sharply in opposite directions after tweet

Musk's announcement saw shares in the social media giant drop by 20% in early electronic trading before Wall Street opened.

His financing plans for the Twitter deal have put pressure on shares in Tesla but after his tweet on Friday, Tesla shares, against which Musk has secured $6.25 billion in funding for the Twitter acquisition, were up about 5%.

Musk's tweet came a day after Twitter fired two of its top managers.

In a memo to employees Twitter, CEO Parag Agrawal said the company has not hit audience growth and revenue milestones. 

Twitter said the company is pausing most hiring, except for critical roles, and is "pulling back on non-labor costs to ensure we are being responsible and efficient."

What's Musk's vision for Twitter?

Musk had said he views Twitter as the "de facto town square" and is not buying the company to make money but instead to protect free speech.

Musk, a prolific Twitter user, also wants to shift the platform away from advertising as its primary revenue source.

He has pledged to reverse Twitter's permanent ban on former US president Donald Trump if his deal to buy the social media giant is successful.

lo/rt (AFP, AP, dpa, Reuters)