"These attacks and the surveillance they have uncovered - combined with the attempts over the past year to further limit free speech on the web - have led us to conclude that we should review the feasibility of our business operations in China," David Drummond, senior vice president of corporate development and chief legal officer, said in a blog post.
"We have decided we are no longer willing to continue censoring our results on Google.cn, and so over the next few weeks we will be discussing with the Chinese government the basis on which we could operate an unfiltered search engine within the law, if at all," he said. Drummond said the company realises that this may well mean having to shut down Google.cn, and potentially its offices in China.
He said that Google detected in December "a highly sophisticated and targeted attack on our corporate infrastructure originating from China that resulted in the theft of intellectual property from Google."
Evidence indicated that the attackers were trying to get access to Gmail accounts of Chinese human rights activists, according to Drummond. At least 20 other large companies including finance, Internet, media and technology were similarly attacked, according to Google.
We are currently in the process of notifying those companies, and we are also working with the relevant US authorities," the statement said.
Expressing serious concerns over the Chinese censorship on Google, US Secretary of State Hillary Clinton has sought an explanation from Beijing in this regard. "We look to the Chinese government for an explanation," Clinton said in a statement after Google officials briefed the State Department over Chinese censorship.
"We have been briefed by Google on these allegations, which raise very serious concerns and questions," she said.
"The ability to operate with confidence in cyberspace is critical in a modern society and economy. I will be giving an address next week on the centrality of internet freedom in the 21st century, and we will have further comment on this matter as the facts become clear," Clinton said.
The company said it also detected that the accounts of dozens of US, China and Europe-based Gmail users who are advocates of human rights in China appear to have been routinely accessed by third parties.
The company's lawyer said that when in January 2006, Google made it clear that "we will carefully monitor conditions in China, including new laws and other restrictions on our services. If we determine that we are unable to achieve the objectives outlined we will not hesitate to reconsider our approach to China."
"We have taken the unusual step of sharing information about these attacks with a broad audience not just because of the security and human rights implications of what we have unearthed, but also because this information goes to the heart of a much bigger global debate about freedom of speech," Drummond said.
"The decision to review our business operations in China has been incredibly hard, and we know that it will have potentially far-reaching consequences," he added.