Thousands of Twitter users are being locked out of their accounts until they manually reset their passwords.
The microblogging site is swamped with users complaining that their details have been reset and they are receiving the following message: "Due to concern that your account may have been compromised in a phishing attack that took place off-Twitter, your password was reset."
Users must then follow a browser link to reinstate the password, which could be a problem for some mobile Tweeters.
We're hearing mutterings that the problem was caused by scammers offering to artificially inflate Twitter follower numbers, though why anyone would want a bunch of fake people following them beggars belief.
Users are also being asked to check their accounts for bogus posts and delete any that are unfamiliar.