The latest warning shots at social media were fired by Wang Chen, a senior propaganda official, who told a meeting of government and Internet company officials this week that Twitter-like microblog services need tighter regulation. Wang reiterated a warning that punishment will be meted out to people who post rumors or falsehoods.

“Microblog sites should strengthen the management of information dissemination, and not provide channels for the spread of rumors,” Wang said, according to a transcript of his speech posted on Sina.com. “Those who fabricate facts and concoct lies online, resulting in serious consequences, should be severely punished according to the law.”

Wang’s remarks, widely reported in state media Friday, came ahead of Saturday’s opening of the annual meeting of the party’s Central Committee and fit with this year’s stated agenda: reforming the cultural system.

Behind the scenes, the 200-plus members of the party elite drawn from the government, the provinces and the military will try to dampen infighting over who will lead China when President Hu Jintao and many in his collective leadership must retire a year from now.

The political transition comes at a time when the leadership wants to flex China’s new power abroad and feels besieged at home by a fast-changing society that feels entitled to make demands on the authoritarian government, with social media amplifying grievances.

Previewing some of the themes the Central Committee will address, the leadership’s propaganda chief Li Changchun last month said China needs a strong “ideological line of defense” to guard against harmful Western influences. He decried declining morality that was fueling public anger at a time of rising protests.

“Money worship, hedonism and extreme individualism are spreading among some members of society. Looking for profit and forgetting righteousness, a lack of integrity, a loss of moral norms are occurring,” Li said in a speech carried by state media. “These problems seriously damage the social atmosphere. The masses’ reaction is strong.”

For a government that is used to controlling what information the public consumes, social media — which encourage individuals to generate content — are proving unnerving. Popular microblogs, or “weibo” in Chinese, helped mobilize 12,000 people in Dalian to successfully demand the relocation of a petrochemical factory and served as an outlet for public anger after a crash on the showcase high-speed rail system in which at least 40 people died.

After the July train crash, “authorities partially lost control of their own spin, their own message, and their own control of public opinion in this information sphere,” said Xiao Qiang, director of the China Internet Project at the University of California-Berkeley. “Weibo was the engine for all these very critical comments that went beyond the railway crash, pointing to the system … to hurt the legitimacy of the regime.”

Chinese microblog sites have also provided independent candidates running for local legislative councils a platform that they have never had before to reach out to the public, Xiao said.

That the government is clamping down anew on social media shows how difficult the technology and society are to control. China unplugged Twitter and Facebook after they were instrumental in anti-government protests in Iran two years ago. To fill the vacuum, Beijing encouraged homegrown alternatives in the belief that domestic companies would be more responsive to government demands.

Those local services caught on quickly, especially with educated middle-class urbanites. The two largest sites run by Sina Corp. and Tencent Holdings Ltd. each claim to have around 200 million users, though it is unclear how many are active. With their explosive growth has come the expectation of frank, even critical discussion, at least by China’s relatively narrow standards.

Beijing isn’t likely to shut down the new services. The warnings from Wang, the vice minister of propaganda, were taken as a sign that the government wants to use social media to get its message out.

Wang urged party officials to take advantage of microblogs, opening accounts to disseminate information more quickly to meet “the urgent demands of strengthening the party and government’s ability to govern in the new era.”

Among the steps Beijing might take to rein in social media are requiring users to register accounts with their real names or imposing a time lag between when comments are posted by users and when they appear on the sites, said Mark Natkin, managing director of Marbridge Consulting, which is based in Beijing and specializes in China’s telecommunications and IT sectors.

New licensing requirements may also be imposed to weed out some companies, concentrating the business among well-established players like Sina which already have systems for expunging undesirable content, he said.

The government, however, will have to proceed cautiously, factoring in how the tens of millions of users will respond to restrictions.

“It’s not just an issue of how unhappy you might be with the change in user experience, it’s also about whether microblogging continues to provide the sort of outlet that people are looking for to express their opinions and exchange information,” Natkin said. “If that’s taken away, something that they’ve already been enjoying for quite some time now, it will feel like a big step backwards and could cause a lot of frustration.”

___

Associated Press writer Charles Hutzler contributed to this report.