A Democratic senator said on Tuesday he has asked 30 U.S. companies, including Apple, Facebook and Skype, for information on their human rights practices in China in the aftermath of Google's decision to no longer cooperate with Chinese Internet censorship efforts.

Google sets a strong example in standing up to the Chinese government's continued failure to respect the fundamental human rights of free expression and privacy, Assistant Senate Majority Leader Dick Durbin said in a statement. I look forward to learning more about whether other American companies are willing to follow Google's lead.

Google, the world's top Internet search engine, said last month it would not abide by Beijing-mandated censorship of its Chinese-language search engine and might quit the Chinese market entirely because of cyber attacks from China.

Durbin, who chairs the Senate Judiciary Subcommittee on Human Rights and the Law, said his panel will hold a hearing in March to question Google and other U.S. companies on their business practices in countries that restrict Internet freedom.

The panel also will hear testimony from high-ranking U.S. government officials on what President Barack Obama's administration is doing to promote Internet freedom, he said.

Meanwhile, Democratic leaders of the Congressional-Executive Commission on China said they would hold a hearing on February 10 to examine the impact of China's Internet policies on humans and development of the commercial rule of law in China.

That watchdog panel was created by U.S. legislation approving China's entry into the WTO in 2001.

Durbin's letter asks each firm for details of its business in China and what, if any, measures it will implement to ensure that its products and services do not facilitate human rights abuses by the Chinese government.

Durbin also urged the companies to join a voluntary code of conduct known as the Global Network Initiative, which regulates the actions of technology firms operating in countries that restrict the Internet and already is backed by Google, Microsoft and Yahoo!

The senior Senate Democrat sent one of four slightly different letters to following 30 companies:

ACER, Amazon, Apple, AT&T, Cisco, Dell, eBay, Facebook, Fortinet, Hewlett-Packard, IAC, IBM, Juniper, Lenovo, McAfee, Motorola, News Corp, Nokia, Nokia Siemens, Oracle, Research In Motion, SAP, Siemens, Skype, Sprint Nextel, Toshiba, Twitter, Verizon, Vodafone and Websense.

(Reporting by Doug Palmer and John Poirier; Editing by Doina Chiacu and Bill Trott)