BEIJING, Dec. 30 -- Nude shows transmitted through online chat-rooms have been brought under effective control after a 3-month police crackdown that started this September.

    Officials in charge of web security from the Ministry of Public Security announced yesterday in Beijing that 90 criminal cases involving online nude shows had been investigated this year, which lead to the arrest of 25 suspects by the end of last month.

    The crackdown also closed a total of 598 pornographic websites and online sex chat-rooms. So far, all domestic porn sites found by the police have been shut down.

    "The campaign has been a success," said Zhao Shiyuan, director of the web security department with the ministry. "I thank all those who offered tip-offs. The police received more than 12,000 leads from the public."

    Zhao said that cyber visitors might easily fall prey to porn sites. Online X-rated chat-rooms that offer nude shows through Web-cams charge visitors for membership fees and usually trap curious individuals or those with unhealthy motives.

    Police have been coming down hard on those suspected of running or performing for such websites and suspects will now face criminal charges though no judicial judgment has yet been made, according to the ministry.

    However, the crackdown has not targeted one-to-one private sex chat through Web-cams.

    "Such private conversations are not against the law, but they are definitely wrong and could lead to potential crimes," said Zhao.

    The ministry said that apart from pornography, junk mails and viruses are also poisoning the Internet.

    The police handled 14,000 cases of online crime last year, five times more than in 2000. Ministry figures also show that more than 80 per cent of domestic Web-surfers are troubled by viruses, and about 60 million junk mails are being sent on the Chinese mainland every day.

    "We must step up the security protection of sites and net users," Zhao said, adding that online security regulations had been released early this month detailing specific technical requirements for site runners.

    Figures from the China Internet Network Information Centre show that the number of Chinese net users has hit 103 million. Among them, 15.8 per cent are minors while 55.1 per cent are between 18 and 30 years of age.