Chinese authorities have shut down 16,000 Internet cafes in the past three months. The communist government - which already restricts free access to the Internet - says the closures are aimed at protecting millions of children from illicit and inappropriate on-line materials.

Two years ago, a fire in one of China's thousands of underground Internet cafés killed 25 people - prompting government closure of the thousands of similar establishments. More recently, in March, two teenagers were killed when they fell asleep on a train track. Authorities said the two had been on computers surfing the web for 48 hours straight at a nearby Internet café.

Now the Chinese government says limiting access to Internet cafes is a pressing public health issue. Communist party officials have compared on-line violence and pornography to the addictive quality of heroin.

Gilles Giheux - the director of the French Centre for Research on Contemporary China in Hong Kong - says that message is finding a receptive audience among China's web-savvy families. "Parents in urban China and middle class parents are worried that their kids are spending too much time in front of the computer, mostly playing games," says Mr. Giheux. He believes Beijing sees Internet regulation as a convenient opportunity to appear responsive to popular concerns.

Middle class families in China increasingly have computers and Internet access at home. But even in China's larger cities less than one third of all families own a computer - so cafes provide access.

Internet cafes are already legally off limits to minors - but the regulations are usually ignored. A study published in China's state controlled newspaper says as many as 15 percent of children in China's cities use Internet cafes.

In an effort to address this problem, China has closed 16,000 cafes in the past three months. And Internet cafes are not allowed within 200 meters of schools or in residential neighborhoods.

Since its introduction to China, the government has tried hard to control the Internet. The sites of many international news outlets are blocked and software has been installed in some Internet cafés to track users' on-line activities.

Nevertheless, unregulated Internet cafes have often escaped strict oversight - with an estimated 60 million Internet users and growing.

Human rights monitors worry about China's latest restriction on Internet access. But Mr. Giheux says the more recent closures probably won't interrupt political activists' access to the Internet, most of whom can access computers at home. He thinks in this case Beijing's target is pleasing parents, not political dissent.

"It's a question of safety, these people would see more regulation of internet cafes as more of an education issue than a political freedom issue," says Mr. Giheux.

In a related effort, the Chinese government has also targeted other media outlets. Newspapers and television stations have been ordered to provide healthier materials for their younger audiences.