Four US technology giants — Google, Yahoo, Microsoft and Cisco Systems — faced a hostile panel on Capitol Hill over their decision to fall in with Chinese censorship of the internet in return for access to the vast and rapidly growing Chinese market.

Executives at the companies were summoned by the House Subcommittee on Global Human Rights after mounting evidence that their technology was being used by the communist regime in Beijing to suppress free speech and target pro-democracy activists.

Yahoo faced the harshest criticism. The company was accused of giving Chinese authorities personal information about users of its e-mail service that led to the jailing of two dissidents. Shi Tao, a journalist who used an anonymous Yahoo e-mail account, was sentenced last year to ten years after sending a government message about the Tainanmen Square massacre anniversary to foreign colleagues.

Chris Smith, the Republican chairman of the committee, also cited a claim by Reporters without Borders that Yahoo handed over data on another of its users, Li Zhi, who was sentenced in December 2003 to eight years in prison for “inciting subversion”.

Drawing parallels with IBM’s collaboration with Nazi Germany, Mr Smith said: “US technology companies today are engaged in a similar sickening collaboration, decapitating the voice of dissidents.” He added: “Women and men are going to the gulag and being tortured as a direct result of information handed over to Chinese officials.”

Yahoo argued that the presence of the internet in China does good, even when censored. Michael Callahan, its general counsel, said that in the case of Shi Tao, Yahoo was unaware of the intentions of the Chinese Government, and when the demand for the information was made, the company was legally obligated to comply with the requirements of Chinese law enforcement.

Harry Wu, who spent 19 years in Chinese labour camps before living in the US, told the panel: “Moral responsibility for Yahoo’s collaboration . . . cannot be shrugged off with a simple assertion that Yahoo had no choice but to co-operate” with the authorities. US technology, he asserted, was a pistol being used to oppress the Chinese people.

Google’s new China-specific search site — Google.cn — blocks many results on politically sensitive terms, such as “Taiwan”, “Tibet” and “Tiananmen Square”.

Mr Smith seeks legislation banning a US company’s ability to censor or divulge information anywhere in the world. Bill Gates, the Microsoft chairman, supports such a law but opposes an outright ban on internet companies working in countries with repressive regimes.

John Palfrey, a Harvard Law School professor, who studies the internet, told The Times that the booming number of bloggers and internet users in China “makes the job of a Chinese censor an impossible job”. He said: “The Chinese Government is going to lose the war.”

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