The co-founder of Twitter said it has been a "tough day" after Bitcoin hackers targeted Barack Obama, Elon Musk, Kanye West and other high-profile users.
A number of accounts, which have large followings, were hacked on Wednesday night and a message was shared asking users to send 1,000 dollars (£794) to a Bitcoin address.
In return, users are told their money will be doubled and returned to them.
Twitter co-founder Jack Dorsey said: “Tough day for us at Twitter. We all feel terrible this happened.”
The hack message read: “I am giving back to my community due to Covid-19! All Bitcoin sent to my address below will be sent back doubled.
“If you send $1,000, I will send back $2,000!
“Only doing this for the next 30 minutes! Enjoy.”
Bill Gates, Democratic presidential candidate Joe Biden and Amazon billionaire Jeff Bezos were among those targeted.
Kanye West’s account was hacked twice in the space of an hour with the same message posted.
Apple, Uber and other company accounts were also hacked.
Most of the tweets have been deleted, but some have been retweeted thousands of times.
Twitter said: “We detected what we believe to be a coordinated social engineering attack by people who successfully targeted some of our employees with access to internal systems and tools.”
Users reported that those with verified accounts, marked by a blue tick, could not send tweets for a brief period – with those who tried shown an error message reading: “Something went wrong, but don’t fret – let’s give it another shot”.
The hacked messages were posted after several high-profile cryptocurrency companies’ Twitter accounts shared malicious links earlier on Wednesday.
Tyler Winklevoss, who founded cryptocurrency company Gemini alongside brother Cameron, tweeted earlier today: “WARNING: @Gemini’s twitter account, along with a number of other crypto twitter accounts, has been hacked.
“This has resulted in @Gemini, @Coinbase, @Binance, and @Coindesk, tweeting about a scam partnership with CryptoForHealth. DO NOT CLICK THE LINK! These tweets are SCAMS.”
His brother Cameron added: “ALL MAJOR CRYPTO TWITTER ACCOUNTS HAVE BEEN COMPROMISED.
“2FA / strong password was used for @Gemini account. We are investigating and hope to have more information shortly.”
