Twitter

The breach "will unfortunately lead to a lot of hacking, targeted phishing and doxxing," Alon Gal, co-founder of Israeli cybersecurity-monitoring firm Hudson Rock, wrote on LinkedIn.

He called it "one of the most significant leaks I've seen."

Twitter has not commented on the report, which Gal first posted about on social media on 24 December, nor responded to inquiries about the breach since that date. It was not clear what action, if any, Twitter has taken to investigate or remediate the issue.

The singer, a headline act for next year's Glastonbury Festival, blamed the platform's "change in policy" around misinformation without elaborating.

Twitter stopped taking action against accounts spreading misleading information about Covid-19 last month.

In response to Sir Elton's announcement, Mr Musk said he hoped the star would be back.

The social media platform normally limits posts to 280 characters.

Twitter said the move was a response to seeing people use the platform to post pictures of longer announcements and steer followers to outside newsletters.

The test will run for two months and involve a small group of writers in Canada, Ghana, the UK and US.

The new feature aims to keep audiences in the Twitter eco-system, with readers able to see a headline and access the longer note by clicking on a link.

The meeting is scheduled for Thursday, and Musk will take questions directly from Twitter employees, the source added.

The news, first reported by Business Insider, comes after Twitter said last week that it anticipated a shareholder vote on the sale by early August.

A Twitter spokesperson confirmed that Musk would attend the company all-hands meeting this week.

Ever since Musk's takeover bid, many Twitter employees have expressed concerns that the billionaire's erratic behavior could destabilize the social media company's business, and hurt it financially.

The Federal Trade Commission (FTC) and the Department of Justice say Twitter violated an agreement it had with regulators, court documents showed.

Twitter had vowed to not give personal information like phone numbers and email addresses to advertisers.

Federal investigators say the social media company broke those rules.

Twitter was fined £400,000 in December 2020 for breaking Europe's GDPR data privacy rules.

The FTC is an independent agency of the US government whose mission is the enforcement of anti-trust law and the promotion of consumer protection.

Mr Musk tweeted that the deal "cannot move forward" unless Twitter backs up its claims that less than 5% of daily users are fake or spam accounts.

Twitter has defended its figures, adding that Mr Musk waived rights to "due diligence" to clinch the deal.

The spat has raised doubts about the takeover.

Analysts have speculated that Mr Musk may be looking for ways to renegotiate the price of the deal or walk away.

Advertising revenue has also been rising, but by less than was forecast.

Some observers have questioned Mr Musk's commercial judgement in buying Twitter, a platform that despite its high profile has not consistently made high returns.

In the latest quarter it made a profit of $513m (£412m) on revenues of $1.2bn.

Daily active users of the platform rose to 229 million, up from 199 million a year earlier, the company said, publishing its latest financial results.

Musk, who made the shock bid less than two weeks ago, has claimed he is the right person to "unlock" the social media firm's "extraordinary potential".

He has suggested a series of changes from relaxing its content restrictions to eradicating fake accounts.

The firm initially rebuffed Musk's bid, but it will now ask shareholders to vote to approve the deal.

It has adopted what is known as a "limited-duration shareholder rights plan", also known as a "poison pill".

The move will prevent anyone from having more than a 15% stake in the company.

It does this by allowing others to buy additional shares at a discount.

The Twitter board detailed its defence plan to the US Securities and Exchange Commission and put out a statement saying it was needed because of Mr Musk's "unsolicited, non-binding proposal to acquire Twitter".

In a surprise announcement, Musk said he would pay $54.20 a share for Twitter, valuing it at about $41b.

It recently emerged that Musk was Twitter's biggest shareholder after he built up a large stake in the firm.

He said that if his offer was not accepted: "I would need to reconsider my position as a shareholder".

A filing with the US financial regulator appeared to show text and/or voice messages from Musk to Twitter's board, showing that he had raised the idea at the weekend that the business should go private.