SHANGHAI, Dec. 2 (Xinhua) -- China's metropolises of Beijing and Shanghai have launched a service that enables metro passengers to use the same QR code to pay ticket fees in both cities.

It is common in China for subway passengers to use a QR code for payments, which is usually scanned at the ticket gates. However, the codes are often on different apps developed in different cities and cannot be used interchangeably.

The service, effective on Tuesday, allows the QR code on the respective apps in Beijing and Shanghai to be accepted for payments in the subway system of both cities.

Authorities in Shanghai said the interconnected payment method is expected to be expanded to more subways systems in other regions.

Beijing and Shanghai have the largest metro networks in China, each handling more than 10 million passenger trips on a daily basis, with frequent travels between the two cities.