Google, Microsoft and Yahoo will be the subjects of a US congressional committee over agreements to censor internet services to Chinese citizens.

Chris Smith, chairman of the house subcommittee that oversees global human rights, has announced that he will hold a hearing on 16 February to investigate the conduct of US technology firms in China.

"It is astounding that Google, whose corporate philosophy is 'Don't be evil', would enable evil by co-operating with China's censorship policies just to make a buck," said Smith, a Republican representing New Jersey.

"China's policy of cutting off the free flow of information is prohibitive for the growth of democracy and the rule of law. Many Chinese have suffered imprisonment and torture in the service of truth, and now Google is collaborating with their persecutors."

Google, Yahoo, Microsoft and Cisco are being asked to attend and explain their behaviour.

Also scheduled to testify are James Keefe, State Department senior advisor for China and Mongolia, Julien Pain from Reporters Without Borders, and Harry Wu from the LaoGai Research Foundation.

It's been a busy week for Google in Washington. Democratic Senator Patrick Leahy sent a letter (PDF) to Attorney General Alberto Gonzales requesting information about the Department of Justice's subpoenas to four major internet companies seeking data on the search habits of millions of Americans. 

Leahy, the ranking Democratic member of the Judiciary Committee, asked in his letter for the types of information the Justice Department was seeking, how the Department intends to use that information while protecting Americans' privacy and civil liberties, and whether the Department will issue any additional subpoenas to internet firms that seek personally identifiable information.