The number of China's 3G mobile telecommunication users reached 18.08 million in March, an increase of 4.83 million from the first quarter, said a senior official with the Ministry of Industry and Information Technology (MIIT) Thursday.

China Mobile took the biggest 3G market share at 42.5 percent, followed by China Telecom at 30.8 percent and China Unicom at 26.7 percent, Zhu Jun, deputy director of the ministry's telecom development department, told a press conference.

The three giant telecommunication operators had invested 6 billion yuan (878.9 million U.S. dollars) in 3G network construction in the first three months, out of the total 95 billion yuan planned for the year, said Xin Guobin, director of the ministry's Performance Inspection and Coordination Bureau.

The ministry said earlier this month that China aimed to have 150 million 3G mobile telecommunication users by 2011 when investment in 3G development would hit 400 billion yuan.

Zhu said at the conference that the Internet industry in China had been expanding and boosting social and economic development.

The number of Internet users rose by about 20 million in the first quarter to hit 404 million in March, Zhu said. China had 191 million subscribers to the country's social networking sites in March.

By the end of 2009, China had 3.23 million domestic websites, said Zhu.