Citi MasterCard credit customers in the U.S. can now begin using Citi Pay, the mobile tap-and-pay service the bank first announced in November.

Citi Pay launched in Singapore, Australia and Mexico in 2016.

Customers with an Android device will have the ability to make in-store purchases via NFC at contactless point-of-sale terminals. Citi Pay is not available as an iOS app, according to a press release.

For online and in-app purchases, Citi customers can use the same Citibank online user ID and password they use to manage their existing online relationship with Citi. According to the release, This capability, resulting from Masterpass integration with Citi Pay, will enable Citi customers to use the service at hundreds of thousands of merchants in 33 countries at launch.

"Whether it is online, on a phone or at a store, we want Citi customers to have seamless, convenient and fast payment options wherever they go," Barry Rodrigues, head of global digital payments at Citi, said in a statement upon the 2016 announcement of Citi Pay. "With more than 100 million customers in the fastest-growing cities in 19 countries, Citi is uniquely positioned to accelerate payment innovation on a global scale. With Citi Pay, we are offering our customers flexibility wherever and whenever they choose to make purchases."