Chinese officials have dismissed claims that its military is behind the vast majority of cyberattacks on the US.
The allegations, published in a report by US security company Mandiant on Tuesday, claimed a 12-storey building in Shanghai was home to a government-sponsored online espionage group. Known as APT1, the group has been targeting US businesses, government organisations and individuals, according to the company.
"The sheer number of APT1 IP addresses concentrated in these Shanghai ranges, coupled with Simplified Chinese keyboard layout settings on APT1's attack systems, betrays the true location and language of the operators," the report said (PDF).
China has refuted the claims, saying IP addresses are not a reliable enough basis for the assertions against it.
The Ministry of Defence said in a statement on Tuesday the report lacks a technical basis to conclude the source of the attacks were from China.
The Ministry said it is common knowledge hackers take over control of an IP address and that well-known uncertainties around attributing online attacks made it irresponsible of Mandiant to publish the allegations. Another problem is that there is no clear legal definition of a network attack, it said.
If IP addresses are evidence, most cyberattacks on China originate from the US, Chinese Foreign Ministry spokesman Hong Lei said on Tuesday, according to China's official news bureau, Xinhua. Beijing also claims a top target is the China People's Liberation Army, Xinhua added.
The country's officials are now highlighting how many attacks originating from foreign nations it suffers. The Foreign Ministry points to figures from China's Computer Emergency Response Team (CNCERT) showing that 73,000 offshore IP addresses controlled 14 million PCs in China and 32,000 IP addresses had control over 38,000 Chinese websites.
In addition, the China's Ministry of National Defence claims its websites had been hit by 240,000 cyberattacks between January and March last year.