US Secretary of State Hillary Clinton on Thursday warned Internet firms to avoid offering the "tools of oppression" to authoritarian Middle East regimes trying to crush democracy protests. Clinton urged private companies to "embrace (their) role in protecting Internet freedom" and ensure protection of ordinary people as well as political activists. Speaking at an Internet conference in The Hague, the chief US diplomat cited cases where "companies' products and services were used as tools of oppression," without naming the companies. "I'd like to discuss three specific challenges that defenders of Internet freedom must confront," Clinton told delegates from more than 20 countries, non-governmental organisations, as well as cyber activists and bloggers. "The first challenge is for the private sector to embrace its role in protecting Internet freedom," Clinton said, adding "in recent months we've seen cases where companies' products and services were used as tools of oppression." Companies have also reportedly turned over sensitive information to governments about dissidents or shut down social networking accounts of activists involved in a political debate, she said. "Today's news stories are about companies selling the hardware and software of repression to authoritarian governments," she told the Google-sponsored gathering. "When companies sell surveillance equipment to the security agency of a Syria, or Iran, or in past times Kadhafi, there can be no doubt that it will be used to violate rights." Activists have used Facebook, Twitter and other Internet technology to organise protests against the rule of Syrian President Bashar al-Assad, Iranian President Mahmoud Ahmadinejad, and the late Libyan leader Moamer Kadhafi. She said "smart companies" decide before being asked by their governments to avoid dealing with countries that use repression. Clinton also warned against bids by repressive governments to use international for it to impose national barriers on the Internet by upending the public-private partnership now governing it. "This approach would be disastrous for Internet freedom. More government control will further constrict what people in repressive environments can do online," Clinton said. Clinton was referring to a Code of Conduct for Information Security that was introduced by Russia, China, Tajikistan and Uzbekistan at the UN General Assembly in September. China's Internet controls have already become a key irritant in relations with the United States, especially after a dispute over Chinese censorship led US search engine giant Google to cut back in China. She said Washington supports the existing "public-private collaboration" that runs the Internet as it evolves in real-time, as well as the principles of multi-stakeholder Internet governance developed by the OECD this year. "A multi-stakeholder system brings together the best of governments, the private sector, and civil society. And it works," she said. In talks before the conference, Dutch Foreign Minister Uri Rosenthal praised Clinton's "great leadership in defending online freedom" as he announced his government was to invest almost six million euros to promote Internet freedom. The money will be spent on initiatives to support bloggers and cyber activists in countries where they were being suppressed. Thai website editor Chiranuch Premchaiporn, editor of the popular Prachtai news website, who faces up to 20 years in jail for remarks posted on her website by others over Thailand's monarchy, praised Clinton for speaking out. "But what is more important than speaking, is to do something about it," she told AFP ahead of the conference.