Without elaborating, Twitter has just posted a help document titled "I'm Having Problems Logging In to UberTwitter or twidroyd" that gives little hope for an immediate fix: turns out the company has outright suspended both apps -- among the most popular Twitter apps for the BlackBerry / iPhone and Android platforms, respectively -- for "violating [its] policies." They go on to say that they suspend "hundreds" of apps on a daily basis for policy violations, but decided to call out these two in particular because of the high number of users potentially affected. Considering the popularity factor, we imagine this'll be solved one way or another before too long -- but in the meantime, you might want to fall back to the official apps for all three platforms.

[Thanks to everyone who sent this in]

Update: We've received a statement on the issue from Twitter, which says that the violations here "include, but aren't limited to, a privacy issue with private Direct Messages longer than 140 characters, trademark infringement, and changing the content of users' Tweets in order to make money." Follow the break for the full text.

Update 2: Pocket-lint says that Echofon is also suspended. Things are getting pretty serious here.

Update 3: UberMedia -- which owns UberTwitter, Twidroyd, and Echofon -- has said that it has "completed the changes, and new apps are currently being posted to their respective stores." They've apparently gotten an assurance from Twitter that the apps will be flipped back on as soon as the changes are live. Oh, also: UberTwitter will become UberSocial, which must be the "trademark infringement" Twitter was referring to.
"We ask all developers in the Twitter ecosystem to abide by a simple set of rules that are in the interests of our users, as well as the health and vitality of the platform as a whole.

We often take actions to enforce these rules; in fact, on an average day we turn off more than one hundred services that violate our API rules of the road. This keeps the ecosystem fair for everyone.

Today we suspended several applications, including UberTwitter, twidroyd and UberCurrent, which have violated Twitter policies and trademarks in a variety of ways. These violations include, but aren't limited to, a privacy issue with private Direct Messages longer than 140 characters, trademark infringement, and changing the content of users' Tweets in order to make money.

We've had conversations with UberMedia, the developer of these applications, about policy violations since April 2010, when they first launched under the name TweetUp – a term commonly used by Twitter users and a trademark violation. We continue to be in contact with UberMedia and hope that they will bring the suspended applications into compliance with our policies soon."

UberMedia's response:

"Early Friday morning, Twitter shut off access to its service by several of our Twitter client applications: UberTwitter, Twidroyd, and UberCurrent. Twitter then notified us that they believed we were in violation of several provisions of their terms of service.

We were immediately in touch with Twitter, and the changes they asked us to make were very small. As a result, we have completed the changes, and new apps are currently being posted to their respective stores. Twitter has assured us that as soon as those changes were complete, they would reactivate our applications.

Twitter also asked us to modify the name of UberTwitter. We began a process of changing the name three weeks ago by polling our users, and we've decided based on their input to change the product name to UberSocial, which we completed today.

To our millions of loyal users, we appreciate your patience during this temporary period. We look forward to continuing our innovations on the Twitter platform."