After the criticism from the government for hosting links to vulgar or pornographic content, three Chinese websites - Baidu, NetEase. com. Inc, and SINA Corp - offered apologies on Wednesday for the alleged inappropriateness. Google's China office too assured to "work hard" with Internet users and society for building an Internet culture with a positive impact.

Other Chinese net companies that apologized late Tuesday included Sohu and Tencent.

In its apology statement posted on the Internet, Baidu, the top search engine in China, said: "We feel deeply guilty. We apologize to Internet users for any negative effects given to society."

The Chinese government, as a part of its customary efforts to block access to Web sites that carry seditious or too political content, had pledged stricter clean-up action this time around for shutting down anomalous websites.

The world's most populous country, China, has the maximum number of Internet users in the world, in excess of 250 million. In spite of the government's extensive and all-encompassing censorship mechanism, pornography is commonly available online.

Though the distribution of pornography is banned, and is punishable under the country's law - which blocks the foreign pornographic Web sites - the "vulgar" materials terminology is yet to be defined clearly.

Wang Qiang, a member of the staff of the Beijing Internet management office - which punishes violators - told the China Daily newspaper the office is looking towards punishment schemes for the much indistinguishable charge of spreading obscene and offensive images.