If you're a Windows Phone user that enjoys watching a YouTube clip from time to time, you may want to hurry up and grab that new YouTube app as soon as possible. The Verge has gotten hold of a letter that Google sent to Microsoft requesting that Redmond firm "immediately withdraw" the new YouTube app from the Windows Phone Store and "disable existing downloads of the application by Wednesday, May 22, 2013." The letter was sent to Todd Brix, General Manager of Windows Phone Apps and Store, and it was sent by Francisco Varela, Director of Global Platform Partnerships at YouTube.

Google appears to have three main complaints about the new YouTube app for Windows Phone, pointing out that the app allows users to download videos from YouTube, avoid viewing ads and to watch clips that are restricted from being played on mobile devices. Google points out that many YouTube video creators make money through ads, so blocking the playback of those ads can have an adverse effect on the people making content. Google also takes issue with the fact that Microsoft has used YouTube's trademarks, citing the YouTube API Branding Guidelines that disallow the use of the YouTube name or logo with an app or service.

Google and Microsoft haven't exactly been buddy-buddy lately, and one example of that is this very YouTube app. Microsoft complained earlier this year that Google was preventing it from offering a fully featured YouTube app on Windows Phone. It appears that Microsoft took things into its own hands, though, as The Verge says that Microsoft made this new YouTube app without Google's permission. Now we've got this new cease and desist letter, which isn't likely to help the strained relationship between these two companies. Microsoft hasn't commented on the matter yet, but it'll certainly be interested to hear what it has to say, so stay tuned and we'll update you if the company issues a statement.

UPDATE: Microsoft has responded to Google's letter, telling The Verge that it's "more than happy to include advertising" in its YouTube app but that it needs Google to give it access to the necessary APIs. "In light of Larry Page’s comments today calling for more interoperability and less negativity, we look forward to solving this matter together for our mutual customers," Microsoft explained.

Via The Verge (1), (2)