The leading US-based Internet firms are showing little interest in attending a Congressional briefing on worries that the firms are bending to the wishes of China's censors.
Microsoft and Cisco Systems have refused to attend the event, while Google and Yahoo are non-committal, officials said.
The firms were asked to attend Wednesday's briefing by the Congressional Human Rights Caucus following uproar caused by search giant Google's decision last week to censor Web sites and content banned by China's propaganda chiefs.
"We have heard from Microsoft that no representative from the company will attend the briefing. So, with Cisco Systems, this makes two companies that have confirmed they're opting out," said Lynne Weil, spokeswoman for caucus co-chairman Democratic Representative Tom Lantos.
As the briefing date gets closer, "others are still unfortunately keeping us in suspense," she said.
"It is mystifying why these companies would not want to take part after all this is an opportunity to clear their names," she said.
Google agreed to censor Web sites and content in its search service launched Wednesday in China. The move followed similar actions by rivals Microsoft and Yahoo in cooperating with Chinese censorship.
Cisco's technology-savvy machinery allegedly censors Internet messages and helps Beijing track down Chinese cyber dissidents.
Americans believed Internet growth will bring about greater freedom of expression and political openness in China but instead of promoting these values, some US firms have been charged with aiding -- or at least complying -- with Chinese Internet censorship, said a statement by the Congressional Human Rights Caucus.
Its briefing is scheduled to be chaired by Democratic Representative Tim Ryan, lead sponsor of a legislation seeking to address China's "manipulation and undervaluation" of its currency.
Weil said all five non-governmental groups invited to the briefing had confirmed participation. They were media watchdog Reporters without Borders, Amnesty International, Human Rights Watch and Toronto University and Harvard Law School.
"It is a sham that the American Internet firms are refusing to be accountable to US Congress and at the same time working hand in glove with the Chinese authorities," said T. Kumar, Amnesty's advocacy director for Asia.
"It is also a paradox that while US multinational companies are for example prohibited from doing any business or trade with Myanmar following human rights sanctions there, Google and others are colluding with the Chinese government in human rights abuses," he said.



