Chinese hack of US national security details revealed days after Russian hack

Government sources tell NBC News that Chinese attack targeted personal emails of 'all top national security' officials just days after Pentagon hack

The ongoing saga of successful foreign hack attacks on government databases continued Monday with news of another break-in allegedly perpetrated by China.

Just days after the reported spear-phishing attack on the Pentagon's joint staff email system, which exposed some 4,000 civilian and military employees and is believed to have been sponsored by Russia, anonymous government sources told NBC News that a separate set of Chinese hack attacks targeted the personal emails of "all top national security and trade officials".