Carlos Barria / Reuters
A general view of 'Unit 61398,' a secretive Chinese military unit on the outskirts of Shanghai on Feb. 19. The unit is believed to be behind a series of hacking attacks, a U.S. computer security company said, prompting a strong denial by China and accusations that it was in fact the victim of U.S. hacking.
The Wall Street Journal and The New York Times reported on Thursday that Chinese hackers repeatedly penetrated their computer systems. NBC's Pete Williams reports.