There has been an 80 percent increase in the number of computer hacking cases handled by the police in China each year since 2006. The new cases posed a threat to both public and national Internet security, a senior police official told China Daily on Wednesday.

"Hacking attacks and the destruction they cause are rapidly increasing. We face a grim situation," Gu Jian, deputy director of the network security bureau of the Ministry of Public Security, said in an interview.

Ministry figures released on Wednesday show that police solved 180 online hacking cases by the end of November, detained 460 suspects and closed 14 websites that provided hacking software or training.

Gu said current hacking cases share the following features:

Profit driven. Hackers make money largely by producing and distributing viruses to steal online bank and game accounts.

Specified tasks. Internet crime has become organized according to chains of interest, with different groups assuming responsibility for different tasks, including producing and selling hacking software, launching attacks, stealing account details and selling them on to others.

Varied victims. Online attacks target a wide range of victims, particularly information concerning the government, business and finance, traffic, electric power, education and scientific research.

Gu cited a case cracked in August, in which the hacking training website Huaxia Hacking Union was shut down by Macheng city police in Central China's Hubei province. Three suspects were detained and 360,000 yuan ($54,000) of illegal profits were seized.

According to the police, the main suspect, surnamed Shi, set up the website in November 2006. To attract traffic, he disseminated botnets (malicious software), which are capable of remotely controlling computers without their users being aware of their system having been compromised.

He also recruited members by selling hacking software and training.

When police closed the website in August, it had recruited about 10,000 members.

Another distinguishing feature of current hacking cases is that suspects frequently use overseas network resources to launch their attacks, which has made it increasingly difficult for the police to track them, Gu said.

Ministry figures show that eight out of every 10 computers connected to the Internet in China have at some point been controlled by botnets, with more than 200 government websites having been attacked by hackers, 80 percent of whom are overseas.