Updated from 5 a.m. EDTHONG KONG ( TheStreet) -- China Unicom ( CHU) said Friday it reached a three-year agreement to sell Apple's ( AAPL) iPhone in China, the world's most populous mobile phone market. The news concerning when Apple would enter the Chinese market was highly anticipated. Sales of the iPhone will begin in the fourth quarter, China Unicom said in a statement Friday. It didn't provide pricing details. Before the agreement between China Unicom and Apple, iPhones were produced in China only by an Apple contractor for export. The deal could help China Unicom better compete with China Mobile ( CHL), which dominates the mobile market. China Unicom said it had 133 million accounts as of Dec. 31, while China Mobile, the world's biggest phone company by subscribers, said it had more than 450 million. "We believe China Unicom's high-speed mobile broadband network, coupled with ... (the iPhone) will create new communication and different experiences for customers in China," said Unicom Chairman and CEO Chang Xiaobin at a news conference. China has about 650 million mobile phone accounts, though its market trails the U.S., Japan and some other markets in financial size. Chinese news reports had previously reported that Unicom secured a three-year exclusive deal to carry the iPhone and agreed to buy 5 million handsets for 10 billion yuan ($1.5 billion). Apple's talks with potential Chinese carriers had snagged on disagreements about how to share revenue, according to Chinese news reports. -- Reported by Joseph Woelfel in New York . Follow TheStreet.com on Twitter and become a fan on Facebook.