introduced its store for Google Android smartphone applications ratcheting up its fight with Apple Inc.

The online retailer also said on Tuesday that the game Angry Birds Rio for Android is available for the first time exclusively through the Amazon AppStore.

Amazon is promoting the game, which is tied to News Corp's Twentieth Century Fox animated film RIO featuring Angry Birds characters, by letting people download it for free for a limited time.

Amazon's AppStore comes one day after Apple sued Amazon in a bid to stop the online retailer from improperly using Apple's App Store trademark.

Amazon's AppStore lets customers test an application before a purchase through their computer using a mouse.

(Reporting by Jennifer Saba; Editing by Derek Caney)