U.S. investigators told Reuters that attackers working for ranging from usernames and passwords for State Department computers to the designs of major weapons systems.

Secret State Dept. cables held by WikiLeaks and given to Reuters by someone else, traced a series of attacks back to the Chinese government - one trace even identifying the specific unit of the Chinese military that launched it.

Code-named "Byzantine Hades," the breaches represent attacks that have been going on since at least 2006 and are accelerating.

The , which compromised the emails of Chinese dissidents and accessed Google source code, also came from China, according to Joel Brenner, .

Thousands of U.S. companies were part of the same series of attacks - code-named "Aurora" - though only 34 were publicly identified, Brenner told Reuters.