BEIJING, Feb. 13 (Xinhua) -- About 20 million UnionPay cards were issued outside the Chinese mainland in 2017, taking the total number of cards issued overseas to about 90 million, the company said on Tuesday.

The transaction volume of these cards grew by about 40 percent year on year.

Over 25 million were issued in the Belt and Road markets, as UnionPay has become the top bankcard in Laos, Mongolia and Myanmar.

More than 4.1 million cards have been issued in . Banks in have issued 1.3 million cards.

China UnionPay is the country's largest bank card payment processor.