Amazon CEO Jeff Bezos Michael Seto The official Amazon app was removed from the Google Play store after Amazon let slip that the app features its own "hidden" app store.

9to5Google reports that Amazon's Android app has had a functional app store inside it since September, but it doesn't look like Google had spotted it.

Generally, app stores don't allow apps to be distributed through them if they directly replicate a function of the app store itself. But this particular ban is more interesting than that: Google and Amazon are in direct competition for shopping search traffic. The war between them has become increasingly heated as Google has sought to blunt Amazon's strong position in search shopping by placing its own shopping ads above certain Amazon results.

Google realised that Amazon had snuck a hidden app store into its own app after Amazon mentioned the store in a press release. The Amazon app was taken down from the Google Play store last night, meaning that Android users couldn't download it.

The "hidden" app store inside the Amazon app. TechCrunch

The app wasn't down for long. Amazon moved quickly to release a new app called "Amazon Shopping." The only difference between that app and its original app is that the hidden app store has been disabled.

Amazon has a different story on what happened to its app. It claims that the app was removed due to Amazon Prime Video. Here's Amazon's side of the story:

We launched a new Amazon App for Android Phones on September 9 that provides an award-winning mobile shopping experience, enables customers to discover and purchase all of Amazon’s digital catalogue, and provides customers access to the Prime Instant Video player and unlimited streaming of over 40,000 movies and TV episodes. Google subsequently changed their Developer Distribution Agreement on September 25. As a result, we removed the app from Google Play and published the Amazon Shopping app. Customers who want the best Amazon experience on their Android phone, including access to Prime Instant Video and Amazon’s entire digital catalog, can still get the Amazon App for Android Phones at amazon.com/androidapp.

Google has moved to try and dominate shopping over the holiday season. It has made its product listing ads (PLAs) more interactive. They're the photos of products that you see at the top of the Google search results when you try and find a product. Amazon doesn't use those ads, meaning it gets hurt when Google expands that service.