Amazon has extended the use of its Amazon Coins virtual currency from Kindle Fire tablets to Android smartphones and tablets for customers in the U.S., U.K. and Germany, according to an announcement from the online retail giant.

Amazon Coins, first launched for purchasing Kindle Apps in May 2013, can now be used to buy apps and play games directly from Android devices. Customers also earn Amazon Coins when they buy apps from the Amazon Appstore using their Android devices or by reaching achievements within certain games.

Amazon said it expanded Amazon Coins across Android devices to help developers build, monetize and market their apps and games. The e-retailer said Amazon Appstore developers will continue to earn their standard 70 percent revenue share when customers make purchases using Amazon Coins.

New and existing Amazon Coins users need to download the latest version of the Amazon Appstore to their mobile device. Customers' Amazon Coin balances are automatically transferred to their Android device and can be spent on more than 100,000 apps and games in the Amazon Appstore.

"Since the launch of Amazon Coins, we've been amazed by the number of customers using Coins, as well as how many Coins they're spending on apps and games," Mike George, vice president, Amazon Appstore and Games, said in a statement. "Because customers can earn Coins when they buy apps in Amazon's Appstore, and because they can buy Coins themselves at up to a 10 percent discount, customers appreciate the extra value they get when shopping in our Appstore."