By Zhang Han and Yao Fei

The man who invented a system that blocked access to websites deemed unsuitable by authorities has shut down his microblog just days after opening it, following a wave of criticism by netizens upset at Internet restrictions in China.

The microblog of Fang Binxing, who helped create the security system dubbed the "Great Firewall of China," was targeted by Internet users who said the security system affected online freedom of speech.

Fang, the president of Beijing University of Posts and Telecommunications, opened his microblog on sina.com a few days ago, but deleted it Monday. No results could be found when a search for Fang's name was conducted on sina. com Tuesday.

Hong Kong-based South China Morning Post reported Tuesday, citing a spokesman from sina.com, that Fang asked the website to remove his posts.

However, a microblog bearing Fang's name and photo can be found on Tencent, another website. One thread says Fang is "honored" to be hailed as the "father of the Great Firewall of China," and that the system can stop subversive activities.

"Fang Binxing, the Great Firewall has deprived people of their right to freely access the Internet," an Internet user wrote on Fang's microblog on sina.com Monday.

A document issued by the general office of the State Council in 2004 said information security of the nation should be strengthened, handling harmful information from both inside and outside the country.

Supporters said the Great Firewall can help protect national security.

Harmful websites, such as pornographic ones, are filtered, but some other popular websites, such as Facebook, Youtube and Twitter, and some search results for sensitive words, are sometimes also blocked, observers said.

Some Internet users were sympathetic to Fang.

"Fang did nothing wrong in inventing such a system, which is quite technologically advanced," a student from the university, speaking on condition of anonymity, told the Global Times.

Bei Feng, an observer of new media development, told the Global Times that the fierce reactions of Internet users reflect their anger at unhappy online experiences caused by the Great Firewall.

Bei said it is necessary for the government to supervise the Internet with clear laws and regulations, which can prevent the misuse of the Great Firewall to block information and websites that are not harmful.

However, he said the effectiveness of the Great Firewall is in question because many Internet users can still access blocked websites through proxy servers and VPNs.