[CNet] In what amounts to a thinly veiled legal threat, the Chinese government has intensified its campaign against sexually explicit material online by instructing companies, including Google, to curb the availability of pornography.

Monday’s announcement from a collection of seven government agencies singles out 19 sites as unlawfully providing access to “vulgar content.” On the list: Google’s Web search and image search, Baidu.net and the company’s blogging site, and Sohu.net. (Google has denied any wrongdoing.)

The announcement from the State Council Information Office is billed as a “nationwide anti-crime” initiative, and urges the public to report illicit posts and Web sites. The state-controlled China Daily said that the companies named on the list “have been found to spread pornography and threaten youth’s morals.” It also warns that a regulatory crackdown may be coming.

While politically themed Internet censorship in China has received most of the attention–news sites and human rights sites are frequently restricted–the country’s ruling Communist Party has long been interested in stamping out smut too. A CNET News article from as far back as 1996 said that Chinese Internet users were asked to “sign a set of rules that makes it illegal for users to produce or receive pornography.”

More recently, the public security ministry said in 2007 that it would target porn, online strip shows, and even erotic stories. Some of the electronic barriers came down during the Olympics last year, only to reappear in the last few weeks.

Along the way, Chinese officials have made some bizarre statements. At an international Internet summit in Athens, a government representative told an incredulous audience: “I’ve heard people say that the BBC is not available in China or that it’s blocked. I’m sure I don’t know why people say this kind of thing. We do not have restrictions at all.” (That statement would come as a surprise to Falun Gong practitioners.)

If this were simply political speech, no doubt members of the U.S. Congress would be tempted to convene ritual hearings where China, Google, and various other companies could be ceremoniously denounced in front of the cameras. But because we’re talking about porn, a Senate resolution applauding China’s censorial policies is probably more likely.