China accused the United States on Thursday of "double standards" and hypocrisy in the area of cyber security as tension flared between Beijing and Washington over the flight of fugitive former spy agency contractor Edward Snowden.
China fired its latest salvo two days after it rejected US accusations it had helped Snowden, who is facing espionage charges in the United States, to escape prosecution by allowing him to leave Hong Kong.
Cyber security is a major irritant between China and the United States and was one of the main topics on the agenda at the first summit between President Xi Jinping and President Barack Obama this month.
Snowden's revelations of widespread snooping by the US National Security Agency in China and Hong Kong have given Beijing considerable ammunition in the tit-for-tat exchange. China's defence ministry said the Prism programme "has revealed the concerned country's true face and hypocritical behaviour".
It did not name the country. Documents previously leaked by Snowden reveal that the National Security Agency has access to vast amounts of Internet data such as emails, chat rooms and video from large companies, including Facebook and Google, under a government programme known as Prism.
"On the one hand, (it) is seeking the advantages of the selfish misuse of information technology, and on the other hand, it is making groundless accusations against other countries," ministry spokesman Yang Yujun told reporters, according to state news agency Xinhua.
"This 'double standard' approach is not conducive to peace and security in cyber space." China has said it was gravely concerned by Snowden's allegations that the United States had hacked into many networks in Hong Kong and China, including Tsinghua University, which hosts one of the country's Internet hubs, and Chinese mobile network companies.
It has said it has taken the issue up with Washington. Snowden has asked Ecuador for asylum and is thought to have remained in transit in Moscow since flying in from Hong Kong on Sunday.