Google is considering puling out of China, after discovering that Chinese hackers tried to break into the mailboxes of Chinese human rights activists.

The e-mail addresses were registered with G-mail, provided by Google. The US internet company said that it was a very advanced attack, which was carried out last month. Twenty other companies were also reported to have been targeted by the hackers.

Google has not specifically pointed the finger at the Chinese government, but says in a official statement that it is no longer willing to apply censorship to the results of its search engine in China.

The company plans to hold talks with the Chinese authorities in the coming weeks. If no agreement can be reached, the Chinese site Google.cn will disappear.