Twitter founder Biz Stone, in a post on the official company blog, said a total of 33 Twitter accounts had been hacked on Monday including those of Obama and Rick Sanchez, a CNN television anchor with tens of thousands of followers.

"We immediately locked down the accounts and investigated the issue," Stone said, nothing that because of "transition issues" Obama has not updated his Twitter account since winning the US presidential election in November.

"These accounts were compromised by an individual who hacked into some of the tools our support team uses to help people do things like edit the email address associated with their Twitter account," Stone said.

According to reports on technology blogs, other prominent "Twitter-ers" whose accounts were hacked included those of Fox News television and singer Spears.

The message from the fake Obama invited recipients to take a survey and win 500 dollars worth of gas while the CNN anchor purportedly told followers that he was "high on crack" and would probably not be coming into work on Monday.

Twitter was also the target of a phishing attack over the weekend in which scamsters attempted to obtain passwords and other personal information from Twitter users.

Stone said that the hacking incident was unrelated to the phishing scam.