Facebook has moved quickly to block users of Twitter's new Vine video-sharing app for iOS from finding other users through their Facebook friends.
In the latest round of tit-for-tat between the two social networking giants, Vine users sinking to bring their Facebook friends into the fold are simply greeted with an error message.
The move will certainly make it more difficult for Vine - announced with great fanfare yesterday - to gain traction, with most people having more Facebook friends than they do Twitter followers.
Facebook's swift sanction could be seen as a direct retaliation for Twitter disabling Instagram photos (owned by Facebook of course) from being embedded within Twitter posts. Now, users have to follow a basic URL link to access snaps on the main Instagram site.
Ironically, Vine has been labelled by many (somewhat lazy) observers as the Instagram of Video. Facebook must be thinking "Not on our watch."
The app allows users to stitch together different video recordings to form a six second video, which plays on loop within a Twitter feed or on the main Vine website.
Whether it can emulate the success of Instagram through the more tricky video medium remains to be seen, but one thing's for sure, Facebook won't be going out of its way to help. Check out our handy guide to other video sharing apps available on the App Store.