TweetDeck has been taken offline in order to address a security issue, and users can't log into the service.
The development comes after the tweet-posting web app had advised users to log out and log back in to apply a fix to a vulnerability. If you're still in TweetDeck, get out now.
An XXS security vulnerability was spotted earlier in the day, a flaw that potentially gave hackers access to users accounts when they were logged in, according to Mashable.
We've asked Twitter for more on the situation and will update this post when we hear back.
James Potter