China Mobile Ltd. said Wednesday its net profit for the January-September period rose 3.9% on growth in its third-generation mobile-services business, even as competition intensified.

The world's largest mobile carrier by subscribers reported net profit for the nine months ended Sept. 30 was 87.25 billion yuan ($13.13 billion), up from 83.94 billion yuan a year earlier.

That marked a slowdown from China Mobile's net profit growth for the first half, when net profit rose 4.2% from a year earlier to 57.64 billion yuan, underlining pressures on the company's bottom line including heavy spending on handset subsidies to promote its 3G services.

China Mobile and its two major rivals, China Unicom (Hong Kong) Ltd. and China Telecom Corp., are competing for subscribers to their 3G services, whose faster data speeds and pricier service plans could boost the companies' average revenue per user—a key gauge to determine long-term growth for telecommunications operators.

China Mobile's average revenue per user fell to 72 yuan in the nine months ended Sept. 30, from 75 yuan a year earlier. The figure has fallen as China Moblie has pushed into less developed regions of China to keep adding subscribers, including users of its cheaper 2G services.

China Telecom is scheduled to report its third-quarter results Oct. 28, followed by China Unicom the next day.

Analysts said China Mobile's introduction of new handsets could boost growth in the firm's 3G business, though subsidies for the handsets and depreciation expenses for the carrier's 3G network are likely to weigh on profitability this year.

The firm said in a statement its average revenue per minute of usage has been declining because of low usage by new customers, while its value-added services business has become the major driver of revenue growth.

China Mobile Chairman Wang Jianzhou said the company will continue to increase investments in areas such as customer services, support systems and research and development to help boost its competitiveness "under the new competitive landscape." A major industry reorganization in China in 2008 resulted in a third wireless operator, China Telecom, competing against China Mobile and China Unicom.

The carrier added 1.86 million 3G subscribers in September, up from 1.585 million in August. Its main rival, China Unicom, added 1.04 million 3G subscribers last month, slightly up from 1.01 million in August.

For the nine-month period, China Mobile's operating revenue rose 7.8% to 352.64 billion yuan from 326.98 billion yuan.