London: Hackers have broken into thousands of accounts on social networking website Twitter and posted spam messages promoting drinks made from acai berries, a media report said Tuesday.
Twitter said the hackers could get the passwords because of an earlier breach at Gawker Media, a company which runs Gawker, Gizmodo and other technology and media sites. People who used the same passwords for Twitter were vulnerable, the Daily Mail reported.
It was, however, not clear how many of Twitter's 175 million users were affected but within hours hundreds of thousands of tweets about acai had been registered.
The problem did not cause a slowdown but has been described by users as "intensely annoying" as it fills up their accounts with spam messages.
Attacks on social networking sites such as Twitter and Facebook are popular because people are more inclined to click on links appearing from friends, rather than email spam, experts said.
The attack came after the Federal Bureau of Investigation (FBI) announced it was planning to investigate the Gawker hacking.
Gawker, which runs a series of blogs on media and technology, said over 1.3 million passwords were stolen.
A file containing password details was then published on a file-sharing site.
A group that calls itself "Gnosis" released a 500 MB file containing the data on file-sharing system Bittorrent so that it can be downloaded by other hackers.
A posting on gawker.com said: "We're deeply embarrassed by this breach. We should not be in the position of relying on the goodwill of the hackers who identified the weakness in our systems."