Musk, who also runs rocket company SpaceX, brain-chip startup Neuralink and tunneling firm the Boring Company, fired Twitter's previous chief Parag Agrawal and other top company officials last week, and has proposed revisions to the platform's user verification process, which has been free until now.

Musk announced his Twitter CEO role in a securities filing. In another filing on Monday, Musk revealed that he had cleaned out the entire board of directors, becaming the sole director of Twitter.

Inner Circle's Top 3 Goals

However, at the same time Musk is removing executives, he is forming a tight circle of advisers, The Wall Street Journal reports. These include three investors familiar with Musk: Ross Gerber, CEO of Gerber Kawasaki Wealth and Investment Management; tech entrepreneur Jason Calacanis; and Sriram Krishnan, a former Twitter product leader.

Three initial objectives Musk has given this inner circle are to expand user verification; improve subscription offerings, including giving users more options to choose the type of content they can see on Twitter; and add ways for content creators to make money on the platform.

Musk had previously changed his Twitter bio to "Chief Twit" in an allusion to his planned move. Twitter on Monday declined to comment on how long Musk might remain CEO or appoint someone else.

"The following persons, who were directors of Twitter prior to the effective time of the merger, are no longer directors of Twitter: Bret Taylor, Parag Agrawal, Omid Kordestani, David Rosenblatt, Martha Lane Fox, Patrick Pichette, Egon Durban, Fei-Fei Li and Mimi Alemayehou," Musk said in the filing.

Shortly afterward, Musk tweeted that the move to dissolve the board "is just temporary," without elaborating.

Replying to a tweeted question on what was "most messed up at Twitter," Musk tweeted on Sunday that "there seem to be 10 people "managing" for every one person coding."

On Monday, Nick Caldwell, a general manager at Twitter's Core Technologies, indicated on his Twitter bio that he was no longer with the company. Caldwell and Twitter did not respond to Reuters' request for comment outside regular business hours.

Fast-Moving

Since the takeover, which concluded last week, Musk has moved quickly to put his stamp on Twitter, which he had ridiculed for months for being slow to introduce product changes or take down spam accounts.

Responding to a tweet from author Stephen King that he would not be willing to pay $20 a month to keep the verified badge on Twitter, Musk replied: "How about $8?"

The billionaire said that introducing a price was the only way to defeat trolls and bots on the platform and that Twitter could not entirely rely on advertisers to pay its bills.

His teams began meeting with some employees to investigate Twitter's software code and understand how aspects of the platform worked, according to two sources familiar with the matter.

Some staff who spoke with Reuters said they had received little communication from Musk or other leaders and were using news reports to piece together what was happening at the company.

Tesla's stock has lost a third of its value since Musk made an offer to buy Twitter in April, compared with a 12% decline in the benchmark S&P 500 index in the same period.