Internet giant Google has threatened to end its operations in China after a cyber attack targeted Chinese human rights activists. The firm said it is no longer willing to censor results on its services in the country.

China has clamped down on the Internet over the last few years and blocked access to a number of sites that can be used for sharing information, such as Twitter and Facebook. Google’s Chinese service only began in 2006 after the firm agreed to censor certain results.

Now the firm has said it no longer wants to censor results in China after a cyber attack, believed to have originated in the country, resulted in the Gmail accounts of a small number of human rights activist being accessed.

“In mid-December, we detected a highly sophisticated and targeted attack on our corporate infrastructure originating from China that resulted in the theft of intellectual property from Google,” said David Drummond, SVP, corporate development and chief legal officer at Google on the company’s official blog.

Drummond added that the attacks were not just targeted at Google, with up to 20 other organisations also being hit. The company also claimed that, “The accounts of dozens of U.S.-, China- and Europe-based Gmail users who are advocates of human rights in China appear to have been routinely accessed by third parties. These accounts have not been accessed through any security breach at Google, but most likely via phishing scams or malware placed on the users’ computers.”

“We have evidence to suggest that a primary goal of the attackers was accessing the Gmail accounts of Chinese human rights activists. Based on our investigation to date we believe their attack did not achieve that objective. Only two Gmail accounts appear to have been accessed,” Drummond said. He added that the content of emails was not accessed.

“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. We have decided we are no longer willing to continue censoring our results on Google.cn,” Drummond said.

He added that the firm will be discussing the matter with the Chinese government over the next few weeks to discuss, “The basis on which we could operate an unfiltered search engine within the law, if at all. We recognize that this may well mean having to shut down Google.cn, and potentially our offices in China.”

China is one of the few markets where Google is not the dominant search engine. Baidu claims around 60% of the market, with Google registering about 26%.