China on Tuesday defended its right to censor the Internet, saying it needed to do so to ensure state security, and cautioned other nations to respect how it polices the world's largest online population.
The government's white paper on the Internet in China -- where more than 400 million people are now online -- comes after a very public row with Google over web freedoms which prompted the US firm to shut down its Chinese search engine.
The Google spat over censorship and cyberattacks touched off a war of words with the United States over Internet freedom, at a time when ties were already suffering over US arms sales to Taiwan and a host of trade and currency issues.
China "advocates the exertion of technical means" in line with existing laws and international norms "to prevent and curb the harmful effects of illegal information on state security, the public interest and minors", it said.
Such laws and regulations allow the curbing of content on everything from "instigating racial hatred or discrimination and jeopardising ethnic unity" to gambling, violence and obscenity, the government noted.
"Effectively protecting Internet security is an important part of China's Internet administration, and an indispensable requirement for protecting state security and the public interest," it said.
Beijing operates a vast system of web censorship, sometimes referred to as the "Great Firewall of China". It blocks access to any content the government deems unacceptable, ranging from pornography to political dissent.
Critics at home and abroad complain that the Internet rules stifle criticism of the ruling Communist Party and restrict discussion on sensitive topics such as Tibet and the brutal crackdown on the 1989 Tiananmen pro-democracy protests.
But China on Tuesday insisted it "guarantees the citizen's freedom of speech on the Internet as well as the public's right to know, to participate, to be heard and to oversee" -- and warned foreign nations to keep quiet on the issue.
"Within Chinese territory, the Internet is under the jurisdiction of Chinese sovereignty. The Internet sovereignty of China should be respected and protected," the government said.
During a visit to China last month, European Commission vice president Neelie Kroes said that Beijing's web censorship constituted a trade barrier that should be looked at by the World Trade Organisation.
Kroes, who is in charge of charting the European Union's digital agenda, said China's "Great Firewall" was a trade issue "as long as that is a real barrier for communication".
According to the New York-based Committee to Protect Journalists, China is among the worst nations in the world oppressing Internet bloggers, and had jailed 24 journalists as of December 2009, many of them Internet bloggers.
The government said in its white paper that it aims to make the Internet available to 45 percent of its 1.3-billion-strong population in the next five years.
It praised the Internet as an "engine promoting the economic development of China" and said the country's leaders "frequently log onto the Internet to get to know the people's wishes" and participate in online chats with users.
Premier Wen Jiabao -- who has tried to forge a reputation as a man of the people, contrasting with his colleagues in the Communist Party hierarchy who come across as much more staid -- has done a few web chats since last year.
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