HONG KONG — The Chinese Health Ministry on Thursday ordered sharp restrictions on Internet access to medical research papers on sexual subjects. It is the latest move in what the ministry calls an antipornography campaign that many China experts see as a harbinger of a broader crackdown on freedom of expression and dissent.
In the past month, central government officials have cited a need to control pornography in ordering that filtering software be preinstalled on all new computers sold in China starting July 1.
They have also forced Google to disable a function that lets the search engine suggest terms and on Wednesday night even briefly blocked access nationwide to Google’s main search engine and other services like Gmail. Some users were still having problems accessing Google sites on Thursday night.
In addition, Chinese bloggers say they have detected evidence of a concerted effort to stain Google’s image. They say that someone in Beijing manipulated Google’s software to make it more likely to suggest a pornographic search term during a state television broadcast.
At the same time, the government seems to have stepped up harassment of human rights advocates.
Liu Xiaobo, one of China’s best-known dissidents, was formally arrested Tuesday on suspicion of subversion, six months after he was detained for joining other intellectuals in signing a document calling for democracy. This month, the authorities refused to renew the licenses of more than a dozen lawyers after they agreed to represent clients in human rights cases.
The same public security agencies charged with fighting pornography are responsible for suppressing illegal political activity, said Nicholas Bequelin, a researcher in Hong Kong for Human Rights Watch. The government’s statistics for seizures of illegal publications tend to include both pornographic and political documents, he noted.
“The two are closely associated,” Mr. Bequelin said. “These campaigns work hand in hand.”
The emphasis on pornography echoes a similar crackdown in late 2005 and early 2006, rights advocates say.
At the time, seeking to allay official Chinese concerns about pornography, Google designed a new search engine for Google.cn, its Chinese service, that would not pull up references to politically delicate subjects like Falun Gong, the banned spiritual movement, or the 1989 killings in and around Tiananmen Square.
While denouncing pornography, propaganda officials reined in publications that were challenging government policies. This included the closing of Freezing Point, a popular journal of news and opinion, and the replacement of top editors at three other publications.
The Health Ministry posted regulations this week requiring medical information providers to restrict access to articles on sexual subjects. The penalty for violations is up to $4,400, with the potential for criminal prosecution for a pattern of uncorrected offenses.
At a news conference on Thursday, a Foreign Ministry spokesman, Qin Gang, was quick to criticize Google for allowing too many links to unseemly sites, saying, “It is every government’s responsibility to protect their teenagers from porn and vulgar information on the Internet.”
On Wednesday, the American commerce secretary, Gary F. Locke, and Ron Kirk, the United States trade representative, sent a letter to Chinese officials protesting the country’s proposal that all computers sold in the country be equipped with filtering software.
“China is putting companies in an untenable position by requiring them, with virtually no public notice, to preinstall software that appears to have broad-based censorship implications and network security issues,” Mr. Locke said in a statement. The United States government did not release the text of the letter.
Asked about the complaint on Thursday, a Chinese Foreign Ministry spokesman said only that he had previously defended the decision to require the software.
Google said Thursday that it was trying to limit access to pornography.
“Google has been working to remove pornography from our search results in China, in accordance with our operating license there,” the company said.
“This has been a major engineering effort,” the company said, “and we believe we have addressed many of the problems identified by the government.”
The government began stepping up pressure on Google last week. CCTV, the state-owned television monopoly, broadcast an interview in which the announcer typed the word “son” into a Google search engine and was dismayed that one of the search terms suggested in Chinese was an “abnormal relationship between son and mother.”
Google’s software makes it possible to analyze the frequency and source of search terms. In a check on Thursday, Google’s Web site showed that no one had entered the phrase “abnormal relationship between son and mother” in Chinese for months until it suddenly became a popular phrase entered only in Beijing in the days before the show, making it more likely that it would pop up as a suggested search term.
The same CCTV show included an interview with a young man, identified as a college student, who expressed horror at pornography on the Internet. Chinese bloggers have since identified the man as an intern for CCTV.
Many Chinese regulations ostensibly aimed at controlling illicit sexual activity could also be used to restrict political activity unacceptable to the authorities.
For example, Chinese law requires that karaoke bars, nightclubs and Internet cafes be monitored 24 hours a day by closed-circuit television cameras on the grounds that prostitutes may try to find clients at such locations. But according to security industry executives, China’s anti-prostitution surveillance regulations are stricter on the Internet cafes.
While nightclubs and karaoke bars are required to store their video records on their premises, Internet cafes must be wired to the nearest police station and provide a continuous, instantaneous record of who is using which computer. If an e-mail message from a cafe’s computer later catches the attention of investigators, the police can review the video records to see who was using the computer.
The last major crackdown on pornography and political expression lasted several months and began to ebb in February 2006, after a dozen former Communist Party officials and senior scholars issued a public letter denouncing the closing of a prominent news journal.
But by then, the government had won some major concessions. Not only had Google agreed to remove considerable political content from its Chinese service, but Microsoft had disabled some blogging activity critical of China, and Yahoo had handed over the identity of an e-mail user who had shared a propaganda directive; the user was sentenced to 10 years in prison.