China Mobile Ltd, the nation's biggest telecom operator by subscriber numbers, is stepping into its most difficult phase financially because of the next-generation network construction and increasingly severe competition in the domestic market, according to analysts.

China Mobile's shares slumped 3.4 percent to HK$ 82.15 ($10.6) on Tuesday, after the company disappointed the market on Monday with a nearly 9 percent drop in its third-quarter net profit.

Analysts argued that China Mobile might have entered its most financial difficult stage and the situation is about to continue "for a while". "China Mobile is progressing with its 4G network deployment and the company will follow its 190 billion yuan guidance in terms of capital expenditure this year," said Deng Liangsheng, an analyst with China Merchants Securities Co Ltd.

"We forecast China Mobile's capital expenditure will maintain a high level next year and that will affect the company's profitability," Deng said.

In a filing to the Hong Kong stock exchange on Monday, China Mobile said its operating revenue in the first three quarters of 2013 reached 463 billion yuan, representing an increase of 9.4 percent over the same period of last year.

Net profit decreased by 1.9 percent year-on-year during the period - the first net income decline since China Mobile's listing in Hong Kong in 1997. Net profit in the third quarter ended Sept 30 was disappointing, as China Mobile recorded a net income of 28.4 billion yuan in the period, down 8.8 percent year-on-year.

China Mobile said that the 4G license issuance will create favorable conditions for the group's transformation but, on the other hand, will add increased pressure to the group's allocation of resources.

Xi Guohua, chairman of China Mobile Ltd, said earlier this year that China Mobile is going to build the world's biggest 4G wireless network in China, covering more than 500 million people in the country. The company will build or upgrade 200,000 4G base stations in 100 Chinese cities by the year end.