Google linked its decision to sophisticated cyberattacks on its computer systems that it suspects originated in China and that were aimed, at least in part, at the Gmail user accounts of Chinese human rights activists.

Those attacks, which Google said took place last week, were directed at some 34 companies or entities, most of them in Silicon Valley, California, according to people with knowledge of Google’s investigation into the matter. The attackers may have succeeded in penetrating elaborate computer security systems and obtaining crucial corporate data and software source codes, though Google said it did not itself suffer losses of that kind…

The company said it would try to negotiate a new arrangement to provide uncensored results of on search site, google.cn. But that is a highly unlikely prospect in a country that has the most sweeping Web filtering system in the world. Google said it would otherwise cease to run google.cn and would consider shutting its offices in China, where it employs some 700 people, many of them highly compensated software engineers, and has an estimated $300 million in annual revenue.