Angry Birds developer Rovio Mobile said that the company has not committed to producing a Windows Phone 7 version of the game.
Microsoft placed the Angry Birds icon on the Windows Phone 7 web site in a section that showcased new applications coming to Microsoft's new smartphone OS.
"We have NOT committed to doing a Windows Phone 7 version. Microsoft put the Angry Birds icon on their site without permission," tweeted Angry Birds developer Rovio Mobile.
Microsoft told CNET that the web site was not supposed to be live yet and that the inclusion of the icon was an error. However the move raises the question as to whether the company has populated the site with other applications which have not yet confirmed Windows Phone 7 versions.
Rovio Mobile later tweeted: "We could do a WP7 version of Angry Birds, not the issue. We have not agreed to do that (yet). Will support all relevant platforms."
Angry Birds is currently available on iPhone and the Android version is due to emerge from Beta this week.