(Clearwisdom.net) Human rights group Amnesty International has fingered a handful of tech companies that allegedly have sold products used in government censorship of Internet speech in China.

In a report released Tuesday, Amnesty said 33 people have been detained in recent years for downloading or distributing politically subversive information via the Internet, three of whom died in custody. Many of these detainees are associated with the Falun Gong spiritual movement and with pro-democracy activities.

Web surfers in China have long reported problems in accessing Web sites, sending and receiving e-mail, and using search engines. It is unclear what technology, if any, the Chinese government currently uses to filter content.

Citing news reports, Amnesty named several U.S.-based companies as alleged suppliers of technology used in the Chinese government's crackdown on Internet speech. These included Sun Microsystems, Cisco Systems, Microsoft, Nortel Networks and filtering software supplier Websense.

In a statement, Microsoft said that it is "focused on delivering the best technology to people throughout the world. However, Microsoft cannot control the way it may ultimately be used."

Websense spokesman Ted Ladd said the company has not entered into any contracts with the Chinese central government. "The report is inaccurate," he said.

Sun, Nortel and Cisco did not immediately respond to requests for comment.

The role of the Internet is a dilemma for China. The government has endorsed the Internet's role in modernizing its economy and has slowly opened its long-coveted telecommunications market to foreign companies. Many foreign tech companies are trying to break into the country's vast and growing market.

The country is home to the second-largest population of Web surfers in the world after the United States, according to market research company WebSideStory.

The government has also introduced strongly worded laws prohibiting the transmission of what it calls "state secrets" to overseas organizations via the Internet. Violators can be sentenced to long imprisonment and death for more serious violations, according to Amnesty's citation of a Chinese law introduced in January 2001.

Amnesty is urging corporations not to do business that could harm basic human rights.

"As China's role as an economic and trading partner grows, multinational companies have a particular responsibility to ensure that their technology is not used to violate fundamental human rights," the group said in a statement.

U.S.-based Web search engines have also felt pressure from the Chinese government. China blocked Google for several weeks in August and blocked AltaVista in September. Web portal Yahoo has defended its decision to sign an agreement to comply with regulations requiring the monitoring and restriction of "harmful" information. Yahoo said it signed the agreement out of compliance with local laws, adding it would not sign any laws that extend beyond current limits of censorship.