BEIJING - China warned Google and other popular Web portals Monday that they must do more to block pornographic material from reaching Chinese users, the latest in a series of government crackdowns targeting Internet content.
The crackdown focused on pornography but is part of a larger Chinese effort to control freedom of expression and root out material it considers destabilizing, such as sites that criticize the Communist Party, promote democratic reform or advocate Taiwan independence.
Pornography is banned in China but remains widely available on and off the Internet. Popular Chinese Web portals frequently show sexually explicit pictures and provide links to pornographic Web sites.
The announcement said Google and Baidu, China's two most heavily used search engines, had failed to take "efficient" measures after receiving notices from the country's Internet watchdog that they were providing links to pornographic material.
Google asserted that it abides by Chinese law and does not generate pornographic content.
The statement also criticized popular Web portals Sina and Sohu, as well as a number of video sharing sites and popular online bulletin boards such as Tianya, that it said contain problematic photos, blogs and postings.
Jeremy Goldkorn, founder of Danwei.org, a Web site that covers Chinese media issues, said such campaigns happen regularly in China to keep Internet sites in line with the government and the mention of Google and Baidu is meant to send a strong message to the whole industry.
"The fact that they rapped every major Web site on the knuckles ... it is sending a message out to be on their best behavior and that's a system that everyone understands," he said.
Charles Freeman, a China specialist at the Washington-based Center for Strategic and International Studies, said the pornography issue was a "stalking horse" for the Chinese government.
"They're looking extensively at political speech, the sort of things traditionally cast under the First Amendment in this country," Freeman said.
He said 2009 is a "very sensitive year politically in China," noting it was 50 years since the Dalai Lama fled Tibet after a failed uprising, 30 years after the democracy wall movement, and 20 years after the crackdown on pro-democracy protesters in Tiananmen Square.
Beijing loosened some media and Internet controls during the 2008 Summer Olympics -- gestures that were meant to show the international community that the games had brought greater freedom to the Chinese people, but blocked The New York Times' Web site on Dec. 19. It was unblocked a couple days later and remained open Monday.
The Chinese government remains wary of losing its control over the Internet, which could be used for organized opposition to the rule of the Communist Party. Last month over 300 lawyers, writers, scholars and artists signed a petition online called "Charter 08", calling for a new constitution guaranteeing human rights.
In the past, the Foreign Ministry has defended China's right to censor Web sites that have material deemed illegal by the government, saying that other countries also regulate Internet usage.
It was unclear what the government classifies as pornographic but it said seven government agencies will work together on the campaign to "purify the Internet's cultural environment and protect the healthy development of minors," the notice said.
The statement, which was posted to a news and information Web site managed by the State Council, said violators will be severely punished, but did not give details. The official Xinhua News Agency said the national campaign would last for one month.
It is unlikely anything other than a fine will be meted out to offenders, Goldkorn said, and the move more likely signifies a need for a quick clean-up ahead of the Chinese Spring Festival, or new year, at the end of this month.
Private Chinese Web sites often hire their own censors to delete sensitive content and images can be erased quickly at the behest of the authorities, he said. This happened early last year when explicit photos of Hong Kong actor Edison Chen and several female partners performing sex acts circulated online. Chinese authorities arrested or detained nearly a dozen people for circulating the photos.
Sexually explicit photos still appeared on online portals Monday, including pictures of actress Zhang Ziyi sunbathing on a beach topless.
A Google spokeswoman in China, Cui Jin, defended the site's operations, saying it is a search engine and does not generate any pornographic content. The company obeys Chinese law, she said.
"If we find any violation, we will take action. So far, I haven't seen any examples of violations," Cui said.
Baidu did not immediately return an e-mail seeking comment, and phones at Sina and Sohu rang unanswered.
China has the world's largest population of Internet users with more than 250 million, and China's attitude to love and sex has changed markedly since it was denounced as a bourgeois decadence under Mao Zedong, a byproduct of rising prosperity and looser government restrictions on private life.
