America's huge dragnet of Internet and phone data, exposed in recent days through leaks and reports, has triggered a heated debate about privacy and national security.
Chinese social media users have made comparisons to their own government, which conducts extensive domestic surveillance and faces mounting accusations of aggressive cyber-spying abroad.
The high-profile outspoken artist said America's behaviour was especially worrying because the country played a leading role in setting Internet norms.
"The US has the edge in technology. It's a leader. Many of the rules about information the ethics, the laws, will be set by these leading countries," Ai told AFP.
Also Read
While the US government faced more limits, he said, both countries were violating citizens' privacy in the name of national security.
"They face different types of restrictions, whether cultural or systematic... But when it comes to invading citizens' privacy there is no difference."
He added that the extent of both countries' surveillance was difficult to compare since much remained unknown.
The leaks and reports have revealed that US government bodies are tapping the servers of nine Internet giants including Apple, Facebook and Google, and collecting a vast sweep of phone records.
A Chinese foreign ministry official in the semi-autonomous city was quoted in Chinese media as saying yesterday that Beijing had not received a request from the US regarding Snowden.
"Not yet," the ministry's commissioner in Hong Kong, Song Zhe, said in response to questions from the Oriental Daily.
Beijing has legal authority to handle defence and foreign affairs in Hong Kong.
Users of China's popular Twitter-like service Sina Weibo offered mixed views.
"Terrorism is pushing the US to quietly centralise more and more power," said one.
China's state-run media has said little of the matter.
Ai surmised: "They do the same thing themselves, so there's not much to say.