China United Network Communications Co Ltd, known as China Unicom, began the commercial rollout of its fourth-generation mobile network on Tuesday, becoming the last of the three Chinese telecom giants to offer such a service, Securities Daily reported.

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The report said China Unicom will offer 4G services in 25 cities, including Beijing, Shanghai, Guangzhou and Shenzhen. It plans to expand the service to about 300 cities by the end of 2014.

The new service marks the beginning of fierce competition in China's 4G market as both China Mobile Ltd, the biggest Chinese telecom operator, and China Telecom Corp Ltd, the country's third-largest carrier, entered the new business sector months ago.

After the Chinese government issued 4G licenses to telecom carriers on Dec 4, 2013, industry analysts expected China to quickly emerge as the world's biggest 4G market, with an estimated subscriber base of 440 million users by 2017.

Miao Wei, the minister of industry and information technology, vowed at the end of last year to boost information consumption and support the rapid development of the 4G market.

Analysts expect reductions in service fees and improvements in 4G technology will create huge potential in the market.

GuoDu Securities Co Ltd estimated that the combined investment from the top three telecom operators in building 4G infrastructure will reach 100 billion yuan ($16.15 billion) this year.

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