Twitter CEO Jack Dorsey’s official account has been hacked, sending racist and vulgar tweets to his 4.2 million followers.
The person tweeting from Mr Dorsey’s account on Friday sent a flurry of offensive tweets such as “Hitler is innocent” and, using a vulgarity, asked “bald skeleton head”, referring to the Twitter chief, to un-suspend his account.
Others from the @jack account used the N-word and made anti-Semitic comments.
Twitter says it is investigating. A group calling itself the Chuckling Squad said it was behind the hacking.
The tweets were up for about 30 minutes before Twitter took them down.
The company also suspended accounts that the hacker or hackers retweeted while they had control of Mr Dorsey’s account.
In a statement, Twitter said: "The account is now secure, and there is no indication that Twitter's systems have been compromised.
"The phone number associated with the account was compromised due to a security oversight by the mobile provider.
"This allowed an unauthorized person to compose and send tweets via text message from the phone number. That issue is now resolved."
The incident comes as Twitter and Mr Dorsey have promised to improve the “health” and civility of discourse on the social media service, cracking down on hate speech and abuse.