Major U.S. Twitter accounts hacked in Bitcoin scam
Billionaires Elon Musk, Jeff Bezos and Bill Gates are among many prominent U.S. figures targeted by hackers on Twitter in an apparent Bitcoin scam.
The official accounts of Barack Obama, Joe Biden and Kanye West also requested donations in the cryptocurrency.
"Everyone is asking me to give back," a tweet from Mr Gates' account said. "You send $1,000, I send you back $2,000."
Twitter said it was a "co-ordinated" attack targeting its employees "with access to internal systems and tools".
"We know they [the hackers] used this access to take control of many highly-visible (including verified) accounts and Tweet on their behalf," the company said in a series of tweets.
It added that "significant steps" were taken to limit access to such internal systems and tools while the company's investigation was ongoing.
By 20:30 EDT (00:30 GMT Thursday) users with verified account started to be able to send tweets again, but Twitter said it was still working on a fix.
Dmitri Alperovitch, who co-founded cyber-security company CrowdStrike, told Reuters: "This appears to be the worst hack of a major social media platform yet."
The tweets were deleted just minutes after they were first posted.
The Twitter accounts targeted all have millions of followers: rapper Kanye West, reality TV star Kim Kardashian, former US President Obama, former US Vice-President Joe Biden, who is the current Democratic presidential candidate, media billionaire Mike Bloomberg and others.