Social networking website Facebook has been accused of blocking the importing capability of Twitter's Facebook app which allows users to find which of your friends are on Facebook.
Twitter told Techcrunch that "Facebook has notified us that they have blocked the update to our application, and we are working on a resolution with them."
A Facebook spokesperson told the Telegraph that they would indicate later why the Twitter app is being blocked and when the issue would be resolved.
However, the application seems to be working fine on Linkedin, the other major social networking website that Twitter added to its roll call.
Launched earlier today, it allows users to connect to Facebook (or Linkedin) people on Twitter and allows you to save these "friends" in a list or follow those who are on Facebook but not on your follow list within seconds.
Although Twitter is significantly smaller than Facebook, the smaller social networking websites has been growing at a faster rate. Facebook tried to acquire Twitter back in 2008 but failed and introduced a feature similar to Twitter's core 140-character service called status update.