February 21, 2013 - American IT security firm, Mandiant, has released a report that identifies what it calls Unit 61398 as a secretive branch of China's military that is dedicated to cyber-hacking and stealing data and secrets from the west, confirming long held fears. China's government has denied the accusation.

Mandiant describes Unit 61398, based in a building in Shanghai, as probably one of the world's "most prolific cyber espionage groups" and says the Chinese unit has "systematically stolen hundreds of terabytes of data" from at least 141 organisations around the world, across 20 industries, including financial services. 87% of the stolen data is from English-speaking countries, adds the cyber security firm.

In a sign of the escalating concern over cyber espionage and corporate spying, the US government said it has taken its concerns about the Mandiant report and cyber-theft generally to the highest levels of China's government.

The detailed Mandiant report investigated hundreds of data breaches going back to the mid-noughties and insists that its extensive work, "convinces us that the groups conducting these activities are based primarily in China and that the Chinese government is aware of them". The firm particularly highlights the APT1 group, which Mandiant numbers at least in the hundreds and has been active since at least 2006 and is a prolific cyber espionage groups. Such extensive and expensive operations are likely to need direct government support or other long-term support, says the firm.

At the turn of the year the 'New York Times' newspaper said its IT systems had been infiltrated over a period of four months, after it ran a series of exposes about corruption in the Chinese government, further heightening tensions.