SHANGHAI (AFP) - China announced Monday it was cracking down on major websites, including search engine giants Google and Baidu, over the spread of pornography and other material that could corrupt young people.

China's Ministry of Public Security and six other government agencies announced the crackdown at a meeting on Monday, the official China Internet Illegal Information Reporting Centre said in a statement.

"For those websites that repeatedly ignore warnings, we will publicise a few, punish a few and even close down a few," Cai Mingzhao, deputy chief of the cabinet's Information Office, said in the statement.

Cai said some websites had taken advantage of government policies and loopholes to publish "low-class, crude and even vulgar contents, which severely corrupted the public mentality".

"The vulgar trend has deeply harmed the mental and physical health of the young generation ... Many parents are calling out: 'Save our children'. They want the government to take drastic action."

The government would initially target 19 Internet service providers and websites that had failed to remove "vulgar" content and had shrugged off censors' warnings, the statement said.

It named Google as having failed to take action on government complaints that its search engine results contained a "massive number of links to pornographic web sites."

"Google has clear policies to protect freedom of expression while not allowing illegal content on our sites in China and elsewhere around the world," a spokesman for the US firm said in response to an AFP inquiry.

"As a search engine, Google does not control the content of the billions of pages in our index."

Baidu is the most popular search engine in China, followed by Google, and it was similarly accused of linking to obscene sites as well as providing blogging services that were used by some people to post vulgar images.

China has launched Internet crackdowns on pornography, con artists and political activists in the past, but officials warned the latest campaign would include tougher measures, without giving specifics.

Aside from its publicly announced crackdowns, China's communist rulers generally exercise extremely strict control over the Internet, blocking access to many politically sensitive sites.

Reporters Without Borders has described China as an "enemy of the Internet" because of its censorship policies.

Monday's announcement comes as China enters a year filled with sensitive anniversaries, including 20 years since the deadly 1989 military crackdown on pro-democracy protesters in Tiananmen Square.

China has the world's largest online population at more that 250 million people, according to official figures, and is growing rapidly as computer use rises along with income levels.