(Adds Google response and Chinese censorship critic's comment)
By Chris Buckley
BEIJING Jan 5 (Reuters) - China has launched a crackdown on websites as the country enters a politically sensitive year, with officials accusing search engines including Baidu (BIDU.O) and Google (GOOG.O) of spreading pornography and vulgarity.
A report on an official news website (www.china.com.cn) said repeated violators and those that had a "malign influence" might be exposed, punished or shut down.
China's Ministry of Public Security and six other government agencies announced the campaign at a meeting on Monday, state television reported, showing officials hauling digital equipment away from one unidentified office.
The meeting "decided to launch a nationwide campaign to clean up a vulgar current on the Internet and named and exposed a large number of violating public morality and harming the physical and mental health of youth and young people," the report said.
The 19 Internet operators and websites named at the meeting had failed to swiftly purge "vulgar" content and ignored warnings from censors, the television report said.
Baidu dominates the Chinese web search market with about two-thirds of the audience. Google Inc, the global market leader, is a distant number two in China.
Cui Jin, a Google public relations officer in Beijing, said she had no comment on the report, but added the company abided by regulations.
"If they (users) find content that is contrary to Chinese law, they can report it to Google. And if we find it's truly illegal, we'll deal with it according to the law," said Cui.
Sun Yao, Baidu's PR representative declined to comment when contacted by Reuters, saying the company was preparing a public comment. Sina.com (SINA.O) was also one of those named and also had no public response.
China's ruling Communist Party is wary of threats to its grip on information and has conducted numerous censorship efforts targeting pornography, political criticism and web scams. But officials flagged tougher steps this time.
The campaign coincides with Communist Party efforts to stifle dissent and protest as the economy slows and China enters a year of sensitive anniversaries, especially the 20th year since the bloody crackdown on pro-democracy protests in 1989.
"Some websites have exploited loopholes in laws and regulations," said Cai Mingzhao, a deputy chief of the State Council Information Office, who chaired the meeting, according to the report on the official website www.china.com.cn.
"They have used all kinds of ways to distribute content that is low-class, crude and even vulgar, gravely damaging mores on the Internet."
The Information Office is the government face of the Communist Party's propaganda arm.
Cai told officials to "fully grasp the gravity and threat of the vulgar current infesting the Internet" and said law-breakers faced "stern punishment".
Despite China's many rings of censorship, websites and especially blogs have become sometimes racy magnets for the country's nearly 300 million registered Internet users, many in their teens.
A list of the 19 named firms, including Baidu and Google, issued by the state-sponsored China Internet Illegal Information Reporting Centre (net.china.cn), said they failed to heed complaints about lude pictures and links to pornography sites.
The official China Daily reported last month that Shanghai police detained a local woman who became an online sensation after posting a video of herself having sex.
Wang Junxiu, a Chinese pioneer of blogging platforms and a critic of censorship, said the crackdown may be more about taming online opinion than stamping out pornography.
"I'd guess that this is in response to all the sensitive dates in 2009. They want to tighten up," Wang told Reuters.
"This is about more than pornography. We've had crackdowns on pornography since the start and they've never worked, so there must be more than that ... It's a warning."
Wang was one of the signatories of the "Charter 08" petition for democratic reform that has recently alarmed officials.
The Financial Times reported on Monday that the Chinese government is arming censors with more advanced filtering software to catch banned content.
(Additional reporting by Michael Wei; Editing by Ken Wills and Dean Yates)