At the recent UN-hosted conference on the Internet, human rights groups warned government censorship on the Internet is growing. Amnesty International singled out China, Vietnam, Iran and Syria, while accusing U.S. companies like Google Inc. of assisting those governments with their filtering; Google has been offering a censored version of its search engine in China.

Google, Microsoft and Yahoo! have already been in the spotlight earlier this year when criticised for aiding foreign governments in filtering the Internet.

Amnesty International said the three firms were in violation of Article 19 of the Universal Declaration of Human Rights, which says everyone should be guaranteed freedom of expression.

Amnesty said some actions the firms had taken, such as Google's refusal to offer an email service in China because of privacy-invasion worries, were good, but more action was needed. In May, Yahoo! said it was seeking the help of the United States Federal Government in urging China to allow more media freedom. It was responding to reports linking information the company gave to Chinese authorities with the jailing of a dissident.