The Facebook Messenger app has begun to alert Windows users that it will "stop working" within a week.

Facebook and Microsoft announced mere days ago at Mobile World Congress 2014 that a Facebook Messenger app for Windows Phone is in the works. Neither company told users that it would simultaneously shut down the Windows desktop version of the app on 3 March.

UPDATE: Facebook Messenger for Firefox will also shut down on 3 March.

In a statement, Facebook confirmed that its two-year-old Facebook Messenger app for Windows will no longer be available from next month. A company spokesperson didn't provide an explanation. In addition, Facebook's official Messenger website has already removed an installer button for the Windows app and now only provides an option for Android and iOS.

Facebook Messenger for Windows originally released in March 2012 after a limited beta test among developers during the year prior. The app, which also exists for Firefox, is an instant messaging service that supports text, voice, and video communication. It is further integrated with Facebook's web-based Chat feature, allowing Facebook users to message and chat with friends whether on desktop, mobile, or on the main website.

READ: Facebook Messenger for iOS updated with stickers and swipe to delete

A Mac OS X version of Facebook Messenger has also been rumoured for quite some time, though it is unclear if that desktop app will ever come to fruition now that Facebook has suddenly killed its desktop messaging clients for Windows and Firefox. We have contacted both Facebook and Microsoft for more information about this abrupt change, and we will update when more information is known.