A sales assistant walks inside a China Mobile store in Guangzhou, Guangdong province, December 18, 2013. [Photo/Agencies]

NEW YORK?-?Apple says it has reached a deal to bring the iPhone to China Mobile, the world's biggest phone carrier.

The deal could boost sales of the iPhone in China. Demand for iPhones, once hugely popular in China, have slumped there as lower-priced rival smartphones from Samsung and Chinese companies entered the market.

The iPhone 5s and 5c will go on sale in Apple stores and China Mobile stores beginning Friday, January 17. Customers can register for phones starting Wednesday December 25.

The companies didn't announce pricing or the terms of their agreement.

The iPhone, while popular around the world, has faced tough competition in recent years from cheaper smartphones running Google's Android software. Collectively, Android phones far outsell Apple's iPhone.

State-owned China Mobile has more than 750 million mobile accounts.